| Title: |
| Spectroscopy of Mrk 231 and NGC 4151 in the 3 mu m Region |
| Authors: |
| IMANISHI, MASATOSHI; TERADA, HIROSHI; GOTO, MIWA; MAIHARA, TOSHINORI |
| Affiliation: |
| AA(National Astronomical Observatory, Mitaka, Tokyo 181-8588; E-mail (MI): imanishi@optik.mtk.nao.ac.jp), AD(Department of Physics, Kyoto University, Kitashirakawa, Kyoto 606-8502 ) |
| Journal: |
| Publ. of the Astronomical Society of Japan, v.50, p.399-404. |
| Publication Date: |
| 08/1998 |
| Origin: |
| PASJ |
| PASJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: INDIVIDUAL (MRK 231, NGC 4151), INFRARED: SPECTRA |
| Abstract Copyright: |
| (c) 1998: Astronomical Society of Japan |
| Bibliographic Code: |
| 1998PASJ...50..399I |
Abstract
We present the results of spectroscopic studies of Mrk 231 and NGC 4151
in the 3 mu m region. In the spectrum of Mrk 231, the strengths of the
3.3 mu m emission feature and the 3.4 mu m carbonaceous absorption
feature are smaller than expected. The weakness of the 3.3 mu m
emission feature implies that large fractions of extended H_{2} emission
detected by Krabbe et al. (1997, AAA 67.158.058) are excited by
SMBH-driven activities, and/or the 3.3 mu m emission carriers in the
circumnuclear starburst region are destroyed by being exposed to
energetic radiation from SMBH-driven activities. The weakness of the 3.4
mu m carbonaceous absorption feature may be due to the destruction of
C--H stretching bonds in dust grains and/or lower abundance of C
relative to Si, O, and Mg than that in our Galaxy, consistent to the
fact that Mrk 231 is now undergoing starburst activities. In the
spectrum of NGC 4151, we detect the broad Bralpha emission line, but do
not detect the 3.3 mu m emission feature nor the 3.4 mu m carbonaceous
absorption feature. The non-detection of the 3.3 mu m emission feature
implies that nuclear starburst activities just outside the obscuring
torus are weak (L_FIR< 3.7 times 10(9) LO ).
| Title: |
| Erratum: ``A Subkiloparsec Disk In Markarian 231'' [Astron. J. 115, 928 (1998)] |
| Authors: |
| CARILLI, C. L.; WROBEL, J. M.; ULVESTAD, J. S. |
| Affiliation: |
| AC(National Radio Astronomy Obervatory) |
| Journal: |
| The Astronomical Journal, Volume 116, Issue 2, pp. 1007-1007. |
| Publication Date: |
| 08/1998 |
| Origin: |
| AJ |
| Abstract Copyright: |
| The American Astronomical Society |
| Bibliographic Code: |
| 1998AJ....116.1007C |
Abstract
The abstract and summary sections incorrectly state that the maximum
radius of the radio continuum disk is 440 mas. The correct statement is
that the major axis of the disk is 440 mas, as given in § 3.1 of
the paper.
| Title: |
| The Emergence of a Quasar from the Luminous Infrared Galaxy Mrk 231 |
| Authors: |
| SMITH, HARDING E.; LONSDALE, CAROL J.; LONSDALE, COLIN J.; DIAMOND, PHILIP J. |
| Affiliation: |
| AA(CASS/UCSD), AB(IPAC/Caltech), AC(Haystack Obs/MIT), AD(NRAO) |
| Journal: |
| American Astronomical Society Meeting, 192, #11.10 |
| Publication Date: |
| 05/1998 |
| Origin: |
| AAS |
| Abstract Copyright: |
| (c) 1998: American Astronomical Society |
| Bibliographic Code: |
| 1998AAS...192.1110S |
Abstract
Mrk 231, a Luminous Infrared Galaxy with log L_{fir} = 12.35(L_sun) is
generally considered to be a dust-enshrouded quasar. Mrk 231 shares many
characteristics with quasars including a broad, Sy1 optical emission
spectrum, optical and radio variability, and broad-absorption-line (BAL)
spectrum. In common with other Luminous IR Galaxies, Mrk 231 is a
molecular-gas-rich system showing evidence for a merger or other
dynamical disturbance in the host galaxy, which is itself a luminous
system with evidence for rapid star formation.
We have obtained VLBI imaging observations in the 18cm continuum and
1667MHz OH maser line. The continuum shows a strong, unresolved nuclear
core with an extended, limb-brightened lobe extending about 30mas (26pc)
to the south, and a much fainter lobe 25mas (21pc) to the north. The
compact radio morphology places it among the Compact Symmetric Objects
(CSOs) in which radio emission originates from hot spots or lobes
symmetrically placed on sub-kpc scales about a central compact source.
It has been suggested that these sources are young, tau << 10(6) yr,
with the hot spots representing the working surface of a relativistic
jet upon the ambient medium. If the southern (primary) lobe/hot-spot in
Mrk 231 is confined by ram pressure, we estimate a lobe advance speed,
v_a 10(-4) c and an age for the jet/compact source, tau < 10(6) yr.
The OH 1667MHz emission is extended over a region of angular dimension
approximately 100 x 50 mas (85 x 43pc) and is probably the inner region
of the disk which is seen in CO emission (Bryant & Scoville 1996, Ap.J.,
457, 678) and HI absorption (Carilli, Wrobel & Ulvestad 1998, A.J., 115,
928). The radio continuum emission associated with this gaseous disk is
likely to be produced by a circumnuclear starburst; if this starburst
has a normal FIR-to-radio ratio, q = 2.34, then up to 2/3 of the
far-infrared continuum in Mrk 231 may come from star-formation. We
suggest that Mrk 231 is a nascent quasar (tau < 10(6) yr) emerging
from its dust-enshrouded starburst phase along the lines of the
evolutionary scenario suggested by Sanders et al.(1988, Ap.J., 325, 74).
| Title: |
| A Subkiloparsec Disk in Markarian 231 |
| Authors: |
| CARILLI, C. L.; WROBEL, J. M.; ULVESTAD, J. S. |
| Affiliation: |
| AC(National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801; ccarilli@nrao.edu) |
| Journal: |
| The Astronomical Journal, Volume 115, Issue 3, pp. 928-937. |
| Publication Date: |
| 03/1998 |
| Origin: |
| AJ |
| AJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: ISM, GALAXIES: SEYFERT, GALAXIES: QUASARS: ABSORPTION LINES, RADIO EMISSION LINES |
| AJ/ApJ Keywords: |
| GALAXIES: INTERACTIONS, GALAXIES: PHOTOMETRY, GALAXIES: STARBURST |
| Abstract Copyright: |
| The American Astronomical Society |
| Bibliographic Code: |
| 1998AJ....115..928C |
Abstract
We present imaging with the Very Long Baseline Array of the neutral
hydrogen 21 cm absorption-line system seen toward the nuclear regions of
Mrk 231 at z_&sun; = 0.04217, and imaging of the radio continuum
emission at 1.4 GHz on scales ranging from a few parsecs to a few
hundred parsecs. These data indicate the existence of a subkiloparsec
gas disk in Mrk 231, as seen in H i 21 cm absorption and in radio
continuum emission. The radio continuum morphology is consistent with a
disk of maximum radius of 440 mas (260 h^-1 pc), at an inclination angle
of 45 deg, with a major axis oriented east-west. The H i 21 cm
absorption shows an east-west gradient in position and velocity of about
+/-110 km s^-1 out to radii of 100 mas (60 h^-1 pc). We identify this H
i and radio continuum disk as the inner part of the molecular disk seen
on a factor of 3 larger scale. The physical conditions for the thermal
and nonthermal gas in the subkiloparsec disk of Mrk 231 are similar to
those proposed for compact nuclear starburst galaxies and, in
particular, to the conditions proposed for the subkiloparsec gas disk in
Arp 220. From the neutral hydrogen velocity field we derive a
gravitational mass enclosed within a 50 h^-1 pc radius of 3 x 10^8 h^-1
M_&sun;, and from the radio continuum emission we derive a massive star
formation rate in the disk of 60 M_&sun; yr^-1.
We also present a search for H i 21 cm absorption associated with the
optical broad absorption line (BAL) systems toward Mrk 231. We do not
detect H i 21 cm absorption associated with any of the optical BAL
systems. These negative results require that the neutral atomic gas in
the BAL clouds be fairly warm (spin temperature T_s > 50 K), unless the
Na i abundance is higher than solar, or the dust-to-gas ratio is higher
than Galactic, or the observed extinction toward the nucleus of Mrk 231
is not due to the BAL gas.
| Title: |
| The Two-Sided VLBI Source in the Seyfert Galaxy Mrk 231 |
| Authors: |
| ULVESTAD, J. S.; WROBEL, J. M.; CARILLI, C. L. |
| Affiliation: |
| National Radio Astronomy Observatory, Socorro, NM, USA |
| Journal: |
| Radio Emission from Galactic and Extragalactic Compact Sources, ASP Conference Series, Volume 144, IAU Colloquium 164, eds. J.A. Zensus, G.B. Taylor, & J.M. Wrobel, p. 199. |
| Publication Date: |
| 00/1998 |
| Origin: |
| AUTHOR |
| Bibliographic Code: |
| 1998rege.conf..199U |
Abstract
The Seyfert 1/starburst/IR galaxy Mrk 231 (UGC 08058), at z=0.0422, has
been imaged with the VLBA at frequencies ranging from 1.4 GHz to 22 GHz.
The radio image shows a triple source of total size 50 mas (30h^{-1}
pc), with a self-absorbed central component and two detached lobes. The
northern lobe, located 12h^{-1} pc from the core, is free-free absorbed
at the lowest frequencies; there also seems to be free-free absorption
in the southern component. The linear scale over which this absorption
takes place is several times larger than that seen in NGC 1275/3C 84.
The axis of the 50-mas radio source is approximately 60 degrees from
the elongation of the central component on the 1-mas scale. The
spectrum of this central component becomes optically thin between 5 and
8.4 GHz, and resolves into a small triple source of size ~1.0h^{-1} pc
at 15 GHz. There is no hint of a jet or other structure directly
connecting this central component to the outer VLBI lobes.
| Title: |
| OSSE Observations of the Ultraluminous Infrared Galaxies Arp 220, Markarian 273, and Markarian 231 |
| Authors: |
| DERMER, C. D.; BLAND-HAWTHORN, J.; CHIANG, J.; MCNARON-BROWN, K. |
| Journal: |
| Astrophysical Journal Letters v.484, p.L121 |
| Publication Date: |
| 08/1997 |
| Origin: |
| APJ |
| Abstract Copyright: |
| (c) 1997: The American Astronomical Society |
| Bibliographic Code: |
| 1997ApJ...484L.121D |
Abstract
We report results of soft gamma-ray observations of the ultraluminous
infrared galaxies Arp 220, Mrk 273, and Mrk 231 in order to test whether
the infrared radiation from these sources originates from buried active
galactic nuclei (AGNs). Only upper limits are measured, implying that
the emergent soft gamma-ray luminosities are 1--2 orders of magnitude
smaller than the infrared luminosities. Monte Carlo simulations of
radiation transport through tori are used to infer the minimum column
densities NH required to block transmission of soft gamma-rays from a
buried AGN, assuming that spectra of AGNs in such sources are similar to
those of radio-quiet quasars. Lack of measured gamma-ray emission
provides no supporting evidence for the existence of buried AGNs in
these galaxies, but is consistent with an origin of the infrared
luminosity from starburst activity.
| Title: |
| Near-Infrared Integral Field Spectroscopy of Markarian 231 |
| Authors: |
| KRABBE, ALFRED; COLINA, LUIS; THATTE, NIRANJAN; KROKER, HARALD |
| Journal: |
| Astrophysical Journal v.476, p.98 |
| Publication Date: |
| 02/1997 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: INDIVIDUAL NAME: MARKARIAN 231, GALAXIES: ISM, GALAXIES: SEYFERT, GALAXIES: STRUCTURE, INFRARED: GALAXIES |
| Abstract Copyright: |
| (c) 1997: The American Astronomical Society |
| Bibliographic Code: |
| 1997ApJ...476...98K |
Abstract
The ultraluminous infrared Seyfert 1 galaxy Mrk 231 has been spectrally
imaged in the K band with the new three-dimensional MPE integral field
spectrometer. The combined images of the H2 emission lines show, for the
first time in an ultraluminous infrared galaxy, the presence of an
extended circumnuclear structure of hot molecular gas. The H2 emitting
region has a size of ~2.4 kpc and a hot molecular gas mass M
^{{hot}}_{{H}_{2}} ~2 x 104 M&sun;. The H2 emission-line ratios indicate
that the gas is most likely thermally excited. If as in NGC 7469 star
formation is associated with the H2 emission, the starburst would have a
far-IR luminosity LFIR ~ 1 x 1012 L&sun;. This value represents an upper
limit, since a fraction of the hot molecular gas may be excited by the
radiation field emerging from the nucleus. The K-band three-dimensional
data cube also shows for the first time the presence of extended narrow
Pa alpha emission blueshifted by ~1400 km s-1 with respect to the
systemic velocity, and located ~0.6 kpc northwest of the nucleus. The
detection of CO absorption bands with a spatial distribution peaking on
the K-band continuum provides evidence for a central stellar
concentration. The low CO spectroscopic index indicates, however,
dilution by hot dust emission or by a nonthermal active galactic
nucleus. The Pa alpha /H alpha ratio confirms previous extinction
measurements based on Balmer line ratios, i.e., visual extinction of AV
~ 2.0--6.6 mag. The quasar-type nucleus of Mrk 231 should then be
transparent at 2 mu m and also in hard X-rays. A weak nuclear He I
lambda 2.058 mu m (He I/Pa alpha = 0.032) is detected, and no detection
of [Si VI] lambda 1.962 mu m is made, placing an upper limit of 4 x
10-18 Wm-2 for the coronal gas emission. The ionizing source could
either be a far-UV and X-ray quiet quasar or else a nuclear starburst
with an upper mass limit >=60 M&sun;.
| Title: |
| The nature of the ionizing source in Mrk 231, an ISO result |
| Authors: |
| RIGOPOULOU, DIMITRA |
| Affiliation: |
| Imperial College, London, Astrophysics Group, Blackett laboratory, ICSTM, Prince Consort Road, London SW7 2BZ, U.K. |
| Journal: |
| Presented at International Astronomical Union. Symposium no. 184. The Central Regions of the Galaxy and Galaxies. Kyoto, Japan, 17-30 August, 1997. |
| Publication Date: |
| 00/1997 |
| Origin: |
| AUTHOR |
| Bibliographic Code: |
| 1997IAUS..184E..73R |
Abstract
We report on ISO spectroscopic observations of the ultraluminous galaxy
MRK 231. Due to large amounts of dust obscuration a reliable assessment
of the source of luminosity at near-infrared wavelengths has always
been difficult. Observations of mid-infrared lines penetrate deep into
the highly obscured regions where the luminosity originates and give
clues to the source(s) of excitation. The small line to continuum
ratios seen with ISO, the warm IRAS 25/60 colors and the absence of
high excitation emission lines, indicate that the active nucleus in MRK
231 is highly obscured by large amounts of dust. Based on these
findings we constrain the properties of MRK 231's source of
luminosity.
| Title: |
| The Two-Sided VLBI Source in Markarian 231 |
| Authors: |
| ULVESTAD, J. S.; WROBEL, J. M. |
| Affiliation: |
| AA(JPL/Caltech), AB(NRAO) |
| Journal: |
| American Astronomical Society Meeting, 188, #05.02 |
| Publication Date: |
| 05/1996 |
| Origin: |
| AAS |
| Abstract Copyright: |
| (c) 1996: American Astronomical Society |
| Bibliographic Code: |
| 1996AAS...188.0502U |
Abstract
Mrk 231 is a dusty Seyfert 1/starburst galaxy at a redshift of 0.0422,
having an extremely high infrared luminosity of about 2x 10(12) L_sun.
Optical images reveal a variety of extranuclear features suggesting that
Mrk 231 underwent a galaxy merger about 10(8) years ago. We have now
imaged the nucleus of Mrk 231, using the VLBA at wavelengths of 6, 13,
and 22 cm to achieve resolutions ranging from 1.5 to 8 milliarcsec. The
galaxy shows a two-sided radio source approximately 50 milliarcsec in
extent, corresponding to a linear diameter of 30 h(-1) pc. The triple
radio source is aligned nearly North-South, in good agreement with the
position angle of the radio structure on scales of tens of arcseconds,
but in contrast with the nearly East-West alignment of the core at
1-milliarcsec resolution. The strong, nearly unresolved central
component (40--120 mJy) has an inverted spectrum, implying that it is
the active nucleus of the galaxy. However, images tapered to the same
resolution at each of the three observing frequencies reveal that the
northern component (1--2 mJy) also has an inverted spectrum. This
component, located 12 h(-1) pc from the core, has a spectral index of
alpha ~ +1.8 (S_nu ~ nu (+alpha ) ) between 22 and 13 cm; the spectrum
flattens out between 13 and 6 cm. This implies that the northern
component is probably free-free absorbed in a manner similar to the
northern component in the radio galaxy 3C 84. Assuming that the
absorption takes place in narrow-line clouds with a temperature near
10,000 K, the inferred emission measure, at a distance of 12 h(-1) pc
from the Mrk 231 nucleus, is approximately 10(7) cm(-6) pc.
| Title: |
| High-Resolution CO Observations of the Ultraluminous Infrared Galaxy Markarian 231 |
| Authors: |
| BRYANT, P. M.; SCOVILLE, N. Z. |
| Journal: |
| Astrophysical Journal v.457, p.678 |
| Publication Date: |
| 02/1996 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: INDIVIDUAL NAME: MARKARIAN 231, GALAXIES: ISM, GALAXIES: KINEMATICS AND DYNAMICS, ISM: MOLECULES |
| Bibliographic Code: |
| 1996ApJ...457..678B |
Abstract
| Title: |
| Echelle Spectroscopy of the Na i D Absorption-Line Systems of Markarian 231 |
| Authors: |
| FORSTER, KARL; RICH, R. MICHAEL; MCCARTHY, JAMES K. |
| Journal: |
| Astrophysical Journal v.450, p.74 |
| Publication Date: |
| 09/1995 |
| Origin: |
| APJ; KNUDSEN |
| ApJ Keywords: |
| GALAXIES: ABUNDANCES, GALAXIES: INDIVIDUAL NAME: MARKARIAN 231, GALAXIES: KINEMATICS AND DYNAMICS, GALAXIES: NUCLEI |
| Bibliographic Code: |
| 1995ApJ...450...74F |
Abstract
| Title: |
| The polarization and ultraviolet spectrum of Markarian 231 |
| Authors: |
| SMITH, PAUL S.; SCHMIDT, GARY D.; ALLEN, RICHARD G.; ANGEL, J. R. P. |
| Affiliation: |
| AAUniversity of Arizona, Tuscon, Arizona, US ABUniversity of Arizona, Tuscon, Arizona, US ACUniversity of Arizona, Tuscon, Arizona, US ADUniversity of Arizona, Tuscon, Arizona, US |
| Journal: |
| Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 444, no. 1, p. 146-156 |
| Publication Date: |
| 05/1995 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTRONOMICAL POLARIMETRY, POLARIZATION (WAVES), POLARIZED RADIATION, SEYFERT GALAXIES, ULTRAVIOLET ASTRONOMY, ULTRAVIOLET SPECTRA, ACTIVE GALACTIC NUCLEI, DILUTION, ELECTROMAGNETIC ABSORPTION, EMISSION SPECTRA, HUBBLE SPACE TELESCOPE, LIGHT SCATTERING |
| Bibliographic Code: |
| 1995ApJ...444..146S |
Abstract
Ultraviolet spectropolarimetry acquired with the Hubble Space Telescope
(HST) of the peculiar Seyfert galaxy Mrk 231 is combined with new
high-quality ground-based measurements to provide the first, nearly
complete, record of its linear polarization from 1575 to 7900 A. The
accompanying ultraviolet spectrum portrays the heavily extinguished
emission-line spectrum of the active nucleus plus the emergence of a
blue continuum shortward of approximately 2400 A. In addition,
absorption features due to He I lambda 3188, Mg I lambda 2853, Mg II
lambda 2798, and especially several resonance multiplets of Fe II are
identified with a well-known optical absorption system blueshifted
approximately 4600 km/s with respect to emission lines. The continuum is
attributed to approximately 10(exp 5) hot, young stars surrounding the
nucleus. This component dilutes the polarized nuclear light, implying
that the intrinsic polarization of the active galactic nucleus (AGN)
spectrum approaches 20% at 2800 A. The rapid decline in degree of
polarization toward longer wavelengths is best explained by the strongly
frequency-dependent scattering cross section of dust grains coupled with
modest starlight dilution. Peculiar S-shaped inflections in both the
degree and position angle of polarization through H alpha and other
major emission lines are interpreted as effects of scattering from two
regions offset in velocity by several hundred km/s. A third source of
(weakly) polarized flux is required to explain a nearly 40 deg rotation
in position angle between 3200 and 1800 A. The displaced absorption
features, polarimetry, and optical/infrared properties of Mrk 231 all
point to its classification as a low-ionization, or Mg II broad
absorption line quasar, in which most, if not all, lines of sight to the
active nucleus are heavily obscured by dust and low-ionization gas
clouds.
| Title: |
| Near-infrared imaging of Markarian 231: Evidence for a double nucleus |
| Authors: |
| ARMUS, L.; SURACE, J. A.; SOIFER, B. T.; MATTHEWS, K.; GRAHAM, J. R.; LARKIN, J. E. |
| Affiliation: |
| AACalifornia Institute of Technology, Pasadena, CA, US ABUniv. of Hawaii, Honolulu, HI, US ACCalifornia Institute of Technology, Pasadena, CA, US ADCalifornia Institute of Technology, Pasadena, CA, US AEUniv. of California, Berkeley, Berkeley, CA, US AFCalifornia Institute of Technology, Pasadena, CA, US |
| Journal: |
| The Astronomical Journal, vol. 108, no. 1, p. 76-83 |
| Publication Date: |
| 07/1994 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| INFRARED ASTRONOMY, MARKARIAN GALAXIES, SEYFERT GALAXIES, SPECTRAL ENERGY DISTRIBUTION, STAR FORMATION, GALACTIC NUCLEI, NEAR INFRARED RADIATION |
| Bibliographic Code: |
| 1994AJ....108...76A |
Abstract
Near-infrared (1.2-2.4 micrometers) images are presented for the central
10 arcsec of the Seyfert 1 galaxy Markarian 231. We find a faint, but
intrinsically luminous (M(sub k) approximately -20.7) secondary peak in
the near-infrared light distribution approximately 3.5 arcsec (2.7 kpc)
south of the primary Seyfert 1 nucleus. Since there is no optical or
infrared evidence for ongoing star formation at the location of this
secondary peak, and its near-infrared luminosity and color are
comparable to slightly reddened spiral bulges or elliptical nuclei, we
identify this peak with the stripped nucleus of the companion galaxy
involved in the Mrk 231 merger event. Depending upon the exact ratio of
the masses of the primary and secondary nucleus in the Mrk 231 system we
estimate a merger time scale of less than or equal to 10(exp 9) yr. The
morphology of the southern nucleus suggests that it may have recently
survived a close passage (r less than 200 pc) with the Seyfert 1 nucleus
on a highly elliptical orbit, in which case the merger time scale may be
significantly shorter (approximately 10(exp 7) yr. We re-calculate the
average merger time scale for the seven ultraluminous infrared galaxies
with double nuclei in the Bright Galaxy Sample (the BGS) of Soifer et
al. (AJ, 98, 766 (1989)) and derive a value of approximately 10(exp 8)
yr. Since seven of ten of the ultraluminous infrared galaxies in the BGS
are now known to be double, we estimate the ultraluminous 'phase' may be
close to this value. Along with Arp 220 and Mrk 273, Mrk 231 is the
third member of the class to possess a high brightness temperature
non-thermal radio core and a double nucleus, suggesting the time scale
for the generation or fueling of the active nucleus can be much less
than the dynamical time scale for the merger of the progenitor nuclei.
| Title: |
| Galaxies with extreme infrared and Fe II emission. 1: Markarian 231: The signature of a young infrared QSO |
| Authors: |
| LIPARI, SEBASTIAN; COLINA, LUIS; MACCHETTO, F. |
| Affiliation: |
| AASpace Telescope Science Inst., Baltimore, MD, US ABUniv. Autonoma, Madrid, Spain ACSpace Telescope Science Inst., Baltimore, MD, US |
| Journal: |
| Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 427, no. 1, p. 174-183 |
| Publication Date: |
| 05/1994 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ACTIVE GALACTIC NUCLEI, DATA REDUCTION, ELLIPTICAL GALAXIES, LIGHT (VISIBLE RADIATION), QUASARS, RADIO EMISSION, SPECTROSCOPY, STAR FORMATION, ULTRAVIOLET SPECTRA, ABSORPTION SPECTRA, CHARGE COUPLED DEVICES, EMISSION SPECTRA, HUBBLE CONSTANT, IUE, LUMINOSITY, SPATIAL RESOLUTION, STELLAR WINDS, TELESCOPES |
| Bibliographic Code: |
| 1994ApJ...427..174L |
Abstract
We investigate the ultraluminous IR Galaxy/QSO Mrk 231 by means of
long-slit optical spectroscopy, high spatial resolution broad-band
optical imaging and UV International Ultraviolet Explorer (IUE) spectra.
The spectrum shows an extreme Fe II optical emission (Fe II(sub OPT)/H
beta approx. equals 8), broad Balmer and Na ID lines, weak
high-excitation lines, double-peaked optical narrow emission lines with
velocity differences of about 1000 km s(exp -1), a steep UV spectrum,
and a weak Ly alpha line. These spectral features are explained 'mainly'
by the presence of nuclear and circumnuclear starbursts. The high
spatial resolution broad-band images show details of two interesting
blue circumnuclear subregions, in particular: (1) a blue region 2 sec-5
sec west of the nucleus; and (2) a blue arc 'horseshoe' at approx. 3.5
sec S. In 'region I' circumnuclear star-forming region located at
approx. 2 sec-5 sec to the west from the nucleus) we detect an
emission-line system (E0) with a velocity (V(sub E0) = 7941 +/- 80 km
s(exp -1)) similar to that of the nuclear system Broad Absorption Line
(BAL)1 V(sub BAL1) approx. 7800 km/s), the strongest of the three broad
absorption-line systems. Moreover, in this region we also detect the
probable presence of this BAL1 system (V(sub NaID) = 7840 +/- 120 km
s(exp -1)). Consequently, Mrk 231 is the first candidate where a direct
link, at least kinematical, between a star-formation process and the BAL
phenomenon is observed. We discuss physical, kinematic and morphological
evidence of a strong nuclear and circumnuclear starburst (with
superwind/superbubble and supernova of Type II), in Mrk 231. These
results and studies are consistent with a scenario where this
ultraluminous IR galaxy has a composite nature inthe nuclear region,
which is the consequence of the final phases of an ongoing merger
process. The starburst is the dominant source of nuclear energy and the
nonthermal active galactic nuclei remains strongly obscured. We also
discuss the extreme properties of Mrk 231 as the probable
characteristics/signature typical of a young IR QSO.
| Title: |
| Ultraviolet Spectropolarimetry of Mrk 231 |
| Authors: |
| SMITH, P. S.; SCHMIDT, G. D.; ALLEN, R. G. |
| Affiliation: |
| AA(Steward Observatory) |
| Journal: |
| American Astronomical Society Meeting, 184, #64.05 |
| Publication Date: |
| 05/1994 |
| Origin: |
| AAS |
| Abstract Copyright: |
| (c) 1994: American Astronomical Society |
| Bibliographic Code: |
| 1994AAS...184.6405S |
Abstract
We present Hubble Space Telescope observations of the peculiar Seyfert 1
galaxy Mrk 231. Ultraviolet (1600--3300 Angstroms ) linear
spectropolarimetric measurements of the object's nuclear region were
obtained using the Faint Object Spectrograph. New ground-based, high
signal-to-noise ratio optical spectropolarimetry is also presented. Both
the degree and position angle of the UV continuum polarization redward
of the Mg II emission line are comparable to the values observed at the
shortest wavelengths accessible to ground-based instruments (P ~ 15%;
theta ~ 90(deg) ). However, from the peak of the redshifted Mg II
emission line through its P-Cygni-like absorption feature, the
polarization is depressed to half that level (similar to the decrease in
P seen in the blue wing of Halpha ). By ~ 2700 Angstroms (observed
frame) the polarization recovers to about 17% but then falls rapidly at
shorter wavelengths. In fact, for lambda < 1800 Angstroms the object
is essentially unpolarized.
The complex wavelength dependence of the UV polarization is evidence
that light from a young stellar population (presumably located around
the active nucleus) dilutes the polarization from the highly reddened
AGN. Unreddened starlight that dominates the flux at wavelengths shorter
than about 2400 Angstroms also explains the abrupt change in the
spectral slope seen in this part of the spectrum. Decomposition of the
AGN and stellar components to the total flux indicates that the
intrinsic polarization of the AGN light exceeds 20% in the UV. In
addition, evidence from optical polarimetry that there is more than one
scattering cloud producing the observed polarization in Mrk 231 is
supported by the fact that theta rotates from 90(deg) to 130(deg)
between 3300 and 1800 Angstroms .
This research is supported by NASA grant NAG 5--1630 and NSF grant AST
91--14087.
| Title: |
| Near-Infrared Observations of the Double Nucleus in Mrk 231 |
| Authors: |
| ARMUS, L.; SURACE, J. A.; SOIFER, B. T.; MATTHEWS, K.; NEUGEBAUER, G.; LARKIN, J. E. |
| Affiliation: |
| AA(Caltech), AB(U. Hawaii), AC(Caltech) |
| Journal: |
| American Astronomical Society Meeting, 183, #46.07 |
| Publication Date: |
| 12/1993 |
| Origin: |
| AAS |
| Abstract Copyright: |
| (c) 1993: American Astronomical Society |
| Bibliographic Code: |
| 1993AAS...183.4607A |
Abstract
We present new near-infrared images in the J, H, and K-band atmospheric
windows of the ultraluminous Seyfert 1 galaxy Markarian 231. These
images show the presence of a faint (K ~15.8 mag), yet intrinsically
very luminous (M ~ -20.4 mag) secondary peak in the light distribution
approximately 3.5 arcseconds, or 2.7 kpc, south of the Seyfert 1
nucleus. The near-infrared luminosity and colors of this peak suggest
it is the remnant nucleus of the companion galaxy to Mrk 231, which,
through an interaction and subsequent merger, has produced the large
scale morphological distortions and fueled the Seyfert 1 nucleus. In
addition, we find extended, warm dust emission surrounding the Seyfert 1
nucleus on scales of 1-3 kpc, suggesting a local heat source which we
identify as a circumnuclear starburst.
| Title: |
| THE NATURE OF THE MILLIMETRE EMISSION IN NGC4102 NGC4418 NGC6000 AND MARKARIAN:231 |
| Authors: |
| ROCHE, P.F.; CHANDLER, C.J. |
| Journal: |
| R.A.S. MONTHLY NOTICES V.265, NO. 2/NOV15, P. 486, 1993 |
| Publication Date: |
| 11/1993 |
| Origin: |
| KNUDSEN; NED |
| Bibliographic Code: |
| 1993MNRAS.265..486R |
Abstract
Millimetre and submillimetre photometry of four galaxies with bright
compact infrared nuclei is presented. The two galaxies with starburst
nuclei have 60 micron-1 mm spectra well fitted by isothermal emission
from cool (~35 K) dust grains with a v^2^ emissivity dependence and no
evidence of emission from a much colder dust component. Non-thermal
nuclear emission and free-free emission arising from the nuclear H II
regions become significant at wavelengths longer than 1 mm, where they
can make a measurable contribution to the flux. The Seyfert galaxy Mrk
231 shows clear excess emission beyond 1 mm above the dust continuum
fitted to the far-infrared and submillimetre photometry. This component
has a flux level that is consistent with an extrapolation of the radio
spectrum attributed to synchrotron emission. The data on the heavily
obscured nucleus of NGC 4418 are more ambiguous. Adequate
representations of the far-infrared to millimetre dust emission can be
obtained with a dust emissivity dependence of between v and v^2^,
depending upon the dust opacity adopted at far-infrared wavelengths. The
photometry shows a weak excess above the dust continuum at wavelengths
beyond 1300 microns, which can partially be accounted for by an
extrapolation of the radio spectrum; the residual excess may be due to
free-free emission. By equating the sizes of the dust emission regions
to those of the compact radio cores in these galaxies, fits to the dust
emission spectra are obtained that are optically thick at mid- and
far-infrared wavelengths in Mrk 231 and NGC 4418, but which are in
approximate agreement with the extinction estimated from the 9.7-micron
silicate absorption features. While there is no evidence of emission
from a cold (<20 K) dust component in any of these galaxies, the
uncertainties in the source size and the dust opacity law at long
wavelengths limit the accuracy with which the dominant cool dust
components can be described.
| Title: |
| Near-infrared imaging of Markarian 231 |
| Authors: |
| KODAIRA, KEIICHI; OHTA, KOUJI; UENO, MUNEKATA |
| Affiliation: |
| AA(National Astronomical Observatory, Mitaka, Japan) AB(Kyoto Univ., Japan) AC(Tokyo Univ., Japan) |
| Journal: |
| PASJ: Publications of the Astronomical Society of Japan (ISSN 0004-6264), vol. 44, no. 6, p. L247-L251. |
| Publication Date: |
| 12/1992 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| INFRARED ASTRONOMY, MARKARIAN GALAXIES, SEYFERT GALAXIES, SPECTRAL ENERGY DISTRIBUTION, STAR FORMATION, GALACTIC NUCLEI, NEAR INFRARED RADIATION |
| Bibliographic Code: |
| 1992PASJ...44L.247K |
Abstract
The initial results of near-infrared imaging observations with a PtSi
camera developed at NAOJ are presented for the central region of a
Seyfert type-l galaxy, Mrk 231. The J-, H-, and K-band images show the
compact nucleus unresolved; their comparison with model images provides
us with upper limits of the brightness of its blue subcomponent relative
to the nucleus: Delta J greater than about 7.1, Delta H greater than
4.6, and Delta K greater than 6.5. This strong constraint in the J band,
in combination with published data for the U band, suggests that the
subcomponent may be a giant star-forming region of M(U) about -18 and
about 10 exp 8 solar masses concentrated within a region of about 2 kpc
across. In FUV observations of Mrk 231, its flux might be dominated by
the emission from this blue object, rather than by that from the heavily
obscured nucleus, itself.
| Title: |
| Absorption line variability in Markarian 231 |
| Authors: |
| KOLLATSCHNY, W.; DIETRICH, M.; HAGEN, H. |
| Affiliation: |
| AB(Universitaets-Sternwarte, Goettingen, Germany) AC(Hamburger Sternwarte, Hamburg, Germany) |
| Journal: |
| Astronomy and Astrophysics (ISSN 0004-6361), vol. 264, no. 1, p. L5-L8. |
| Publication Date: |
| 10/1992 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ABSORPTION SPECTRA, MARKARIAN GALAXIES, SEYFERT GALAXIES, LIGHT CURVE, RED SHIFT, SODIUM |
| Bibliographic Code: |
| 1992A&A...264L...5K |
Abstract
We present optical spectra of Mkn231 for three different epochs. Through
comparison with spectra from the literature of the last 15 years, we
have determined a variability lightcurve for one of the three nonstellar
NaD absorption components, namely the one having the highest relative
velocity of 8000 km/s with respect to the systemic velocity. The other
NaD absorption components and the continuum flux remained constant
during the last 10 years. The amplitude of the variable absorption
component shows a FWHM of 2500 days. From this value we derive an upper
limit of 8 light days for the extension of the central continuum source
in Mkn231 or a lifetime of 10 years for the varying absorption line
cloud.
| Title: |
| Mid-infrared imaging of Markarian 231 and Arp 220 |
| Authors: |
| KETO, ERIC; BALL, ROGER; ARENS, JOHN; JERNIGAN, GARRETT; MEIXNER, MARGARET |
| Affiliation: |
| AA(NASA, Infrared Telescope Facility, Mauna Kea, HI; Smithsonian Astrophysical Observatory, Cambridge, MA; Lawrence Livermore National Laboratory, Livermore, CA) AB(NASA, Infrared Telescope Facility, Mauna Kea, HI; Lawrence Livermore National Laboratory, Livermore; California, University, Berkeley) AC(NASA, Infrared Telescope Facility, Mauna Kea, HI; California, University, Berkeley) AD(California, University, Berkeley) AE(NASA, Infrared Telescope Facility, Mauna Kea, HI; California, University, Berkeley) |
| Journal: |
| Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X), vol. 387, March 1, 1992, p. L17-L19. |
| Publication Date: |
| 03/1992 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| GALACTIC NUCLEI, INFRARED IMAGERY, MARKARIAN GALAXIES, QUASARS, SEYFERT GALAXIES, ABSORPTION SPECTRA, ANGULAR RESOLUTION, FAR INFRARED RADIATION, INTERSTELLAR GAS, RADIO EMISSION |
| Bibliographic Code: |
| 1992ApJ...387L..17K |
Abstract
High angular resolution observations of Arp 220 and Mrk 231 provide
images of the nuclei and show that the source of the strong mid-IR
emission is confined to regions less than about 0.5 arcsec or 400 pc in
diameter in Mrk 231 and less than 1.5 arcsec x 0.9 arcsec or 320 x 530
pc in Arp 220. If much of the far-IR emission also derives from such a
small region, the implied radiation densities are quite high, equivalent
to one O star per cu pc. Although in normal galaxies the near-IR traces
an older population of evolved, cool stars, such high radiation
densities in the IR bright galaxies suggest the possibility that the
spatial correlation observed between the near-IR, mid-IR, and radio may
hold because emission in all three bands is associated with hot
interstellar gas and dust.
| Title: |
| A SHADOW OVER THE FACE OF MARKARIAN:231 |
| Journal: |
| SKY AND TELESCOPE V. 82, NO. 1/JUL, P. 9, 1991 |
| Publication Date: |
| 07/1991 |
| Origin: |
| KNUDSEN |
| Bibliographic Code: |
| 1991S&T....82S...9. |
Abstract
Not Available
| Title: |
| The appearance of a new redshift system in Markarian 231 |
| Authors: |
| BOROSON, TODD A.; MEYERS, KARIE A.; MORRIS, SIMON L.; PERSSON, S. E. |
| Affiliation: |
| AB(Kitt Peak National Observatory, Tucson, AZ) AD(Observatories of the Carnegie Institution, Pasadena, CA) |
| Journal: |
| Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X), vol. 370, March 20, 1991, p. L19-L21. |
| Publication Date: |
| 03/1991 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ACTIVE GALACTIC NUCLEI, MARKARIAN GALAXIES, RED SHIFT, ABSORPTION SPECTRA, ASTRONOMICAL SPECTROSCOPY |
| Bibliographic Code: |
| 1991ApJ...370L..19B |
Abstract
Spectroscopic observations made in 1988 of Markarian 231 show that a new
absorption redshift system has appeared. This system is seen in the Na I
D lines and the He I 3889 line. Its redshift is 4660 km/s, which is 8240
km/s less than the systemic velocity. These lines were not present in
any published spectra obtained through December 1984. This is an
extremely dramatic case of variation in the spectrum of a broad
absorption line AGN. Unlike other cases of variation which have been
interpreted as due to changes in ionization of the absorbing cloud, the
new system is more readily explained as the motion of a cloud with some
transverse velocity into the line of sight.
| Title: |
| HCN Emission from Markarian 231 |
| Authors: |
| SOLOMON, P.; BARRETT, J.; RADFORD, S.; DOWNES, D.; SAGE, L. |
| Journal: |
| IAU Circ., 5027, 3 (1990). Edited by Green, D. W. E. |
| Publication Date: |
| 05/1990 |
| Origin: |
| CBAT |
| Objects: |
| Mkn 231 |
| Bibliographic Code: |
| 1990IAUC.5027....3S |
Abstract
IAUC 5027 available courtesy of the Central Bureau for Astronomical Telegrams.
IAUC 5027 available courtesy of the Central Bureau for Astronomical Telegrams.
| Title: |
| TRIGGERING QUASARS / IRAS:00275-2859 / PG:1613+65 / MARKARIAN:231 |
| Journal: |
| SKY AND TELESCOPE V. 75, NO. 3/MAR, P.247, 1988 |
| Publication Date: |
| 03/1988 |
| Origin: |
| KNUDSEN |
| Bibliographic Code: |
| 1988S&T....75V.247. |
Abstract
Not Available
| Title: |
| The X-ray properties of two galaxies with high far-infrared luminosities - Arp 220 and Markarian 231 |
| Authors: |
| EALES, S. A.; ARNAUD, K. A. |
| Affiliation: |
| AA(Hawaii, University, Honolulu) AB(Harvard-Smithsonian Center for Astrophysics, Cambridge) |
| Journal: |
| Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 324, Jan. 1, 1988, p. 193-197. |
| Publication Date: |
| 01/1988 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ACTIVE GALACTIC NUCLEI, ASTRONOMICAL SPECTROSCOPY, FAR INFRARED RADIATION, GALACTIC STRUCTURE, MARKARIAN GALAXIES, X RAY SOURCES, ABSORPTION SPECTRA, EMISSION SPECTRA |
| Bibliographic Code: |
| 1988ApJ...324..193E |
Abstract
The Einstein X-ray data for the two luminous infrared galaxies, Arp 220
and Markarian 231 have been analyzed. There is an X-ray source about 1
arcmin from the position of Arp 220 that is probably associated with it.
Mrk 231 was not detected. The size of the source and its soft X-ray
spectrum implies that the bulk of the X-ray emission from Arp 220 cannot
be coming from the obscured active nucleus at the galaxy's center. The
absence of strong X-ray emission from the active nuclei in Arp 220 and
Mrk 231 suggests that there must be more line-of-sight absorption to the
active nuclei than is inferred from many of the absorption indicators
available.
| Title: |
| The host galaxy of Markarian 231 |
| Authors: |
| HAMILTON, DONALD; KEEL, WILLIAM C. |
| Affiliation: |
| AB(National Optical Astronomy Observatories, Tucson, AZ) |
| Journal: |
| Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 321, Oct. 1, 1987, p. 211-224. |
| Publication Date: |
| 10/1987 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| GALACTIC STRUCTURE, H ALPHA LINE, IONIZED GASES, MARKARIAN GALAXIES, STAR FORMATION, UBV SPECTRA, ASTRONOMICAL SPECTROSCOPY, GALACTIC NUCLEI, INTERSTELLAR EXTINCTION, SPECTRAL LINE WIDTH |
| Bibliographic Code: |
| 1987ApJ...321..211H |
Abstract
Digital images and spectra of the host galaxy of Markarian 231 are
presented. Its morphology does not fall within standard classification
schemes, but suggests a merger or other violent dynamical disturbance.
Spectral features from a young stellar population and ionized gas are
present, and the stellar population is younger than normally found in
high-luminosity galaxies of any type. H II region-like emission is found
only in one area; spectroscopic data suggest a sudden, galaxy-wide
cutoff in star formation or show a less extreme, but unusually young,
stellar population. A spatially resolved narrow-line region has been
identified, of unusually low density and extent about 10 kpc. Gas
further out in the galaxy is contiguous with this narrow-line region and
appears to be ionized by the nuclear continuum (or possible shocks), but
is of such low ionization that the extinction on nearly all lines of
sight must be comparable to that presently observed; that is, the clouds
responsible for reddening the nuclear continuum have a covering factor
near unity.
| Title: |
| The size of Mrk 231 at 10 microns |
| Authors: |
| MATTHEWS, K.; NEUGEBAUER, G.; MCGILL, J.; SOIFER, B. T. |
| Affiliation: |
| AD(Palomar Observatory, Pasadena, CA) |
| Journal: |
| Astronomical Journal (ISSN 0004-6256), vol. 94, Aug. 1987, p. 297-299. NSF-supported research. |
| Publication Date: |
| 08/1987 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTROMETRY, ASTRONOMICAL SPECTROSCOPY, QUASARS, RADIO SPECTRA, SEYFERT GALAXIES, SPATIAL RESOLUTION, GALACTIC EVOLUTION, GALACTIC NUCLEI, SIZE (DIMENSIONS), SPECTRUM ANALYSIS |
| Bibliographic Code: |
| 1987AJ.....94..297M |
Abstract
A new technique is demonstrated for using the signal from a source at a
wavelength where it is strong to assist in determining its size at
another wavelength. Observations of the size of the nucleus of Mrk 231
at 10 microns are consistent with a picture of a single luminosity
source, perhaps obscured by dust. The variation with wavelength of the
emissivity of the grains is constrained to be less than (wavelength) -
1. The measurements are inconsistent with Mrk 231 being a starburst
galaxy with a luminosity density similar to that of M82.
| Title: |
| High-resolution surface photometry of Markarian 231 in the U band |
| Authors: |
| KODAIRA, K.; OKAMURA, S.; STOCKTON, A. |
| Affiliation: |
| AB(Tokyo Astronomical Observatory, Mitaka, Japan) AC(Hawaii, University, Honolulu) |
| Journal: |
| Astronomical Society of the Pacific, Publications (ISSN 0004-6280), vol. 99, May 1987, p. 375-379. |
| Publication Date: |
| 05/1987 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTRONOMICAL SPECTROSCOPY, SEYFERT GALAXIES, SURFACE PROPERTIES, ULTRAVIOLET SPECTRA, ASTRONOMICAL PHOTOMETRY, GALACTIC STRUCTURE |
| Bibliographic Code: |
| 1987PASP...99..375K |
Abstract
Surface photometry of Markarian 231 has been obtained from
high-resolution plates in the U band. The nuclear region is found to
show a clear two-component structure. The two-dimensional luminosity
distribution has been decomposed into the two nuclear components and the
main body, and characteristic parameters have been derived for each
component. The results of the present study suggest that the host galaxy
of Mrk 231 is not a giant elliptical galaxy in the process of
assimilating an irregular or late-type spiral galaxy, but a giant spiral
galaxy disturbed by the tidal interaction.
| Title: |
| Detection of CO(1-0) emission and optical imaging of the Seyfert galaxy/QSO Markarian 231 |
| Authors: |
| SANDERS, D. B.; SCOVILLE, N. Z.; SOIFER, B. T.; YOUNG, J. S.; DANIELSON, G. E. |
| Affiliation: |
| AC(Palomar Observatory, Pasadena, CA) AD(Five College Radio Astronomy Observatory, Amherst, MA) AE(Palomar Observatory; California Institute of Technology, Pasadena) |
| Journal: |
| Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X), vol. 312, Jan. 1, 1987, p. L5-L9. |
| Publication Date: |
| 01/1987 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| CARBON MONOXIDE, GALACTIC RADIATION, INFRARED ASTRONOMY, SEYFERT GALAXIES, CHARGE COUPLED DEVICES, EMISSION SPECTRA, GALACTIC STRUCTURE, INTERSTELLAR GAS, STARBURST GALAXIES |
| Bibliographic Code: |
| 1987ApJ...312L...5S |
Abstract
The detection of CO(J = 1-0) emission and optical imaging of the
luminous infrared galaxy Markarian 231 are reported. The galaxy is
extremely rich in molecular gas with MT(H2) approximately equal to 1.4 x
10 to the 10th solar masses, approximately 5 times the molecular gas
content of the Galaxy. Markarian 231 is the most luminous object in the
local universe (z approximately equal to or less than 0.1), with a
far-infrared luminosity (lambda = 40-400 microns) of 2.1 x 10 to the
12th solar luminosities. THe CO detection yields a L(FIR)/M(H2) ratio of
150. A deep optical CCD image shows two striking tidal tails with total
extent of about 75 kpc. The CCD image strongly suggests that Markarian
231 is an advanced merger system. If the molecular gas is highly
concentrated in the nuclear region it may fuel an intense starburst and
possibly feed the accretion onto an embedded QSO. The trigger for the
intense activity observed in Markarian 231 appears to be the collision
of two gas-rich spiral galaxies.
| Title: |
| Morphology and nuclear spectroscopy of Markarian 231 |
| Authors: |
| HUTCHINGS, J. B.; NEFF, S. G. |
| Affiliation: |
| AA(Dominion Astrophysical Observatory, Victoria, Canada) AB(NASA, Goddard Space Flight Center, Greenbelt, MD) |
| Journal: |
| Astronomical Journal (ISSN 0004-6256), vol. 93, Jan. 1987, p. 14-21. |
| Publication Date: |
| 01/1987 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTRONOMICAL SPECTROSCOPY, GALACTIC NUCLEI, IUE, SEYFERT GALAXIES, ULTRAVIOLET SPECTRA, ABSORPTION SPECTRA, INFRARED ASTRONOMY, LINE SPECTRA, MORPHOLOGY, VERY LONG BASE INTERFEROMETRY |
| Bibliographic Code: |
| 1987AJ.....93...14H |
Abstract
Deep optical imaging of Mkn 231 reveals twin (tidal?) tails, a linear
nuclear feature at green wavelengths, and a very blue region 4 arcsec
south of the nucleus. Much of the central part of the galaxy is red, but
there are complex areas of blue luminosity outside this, and a sharp
edge to the luminosity at a distance of about 16 arcsec from the center.
Overall, the host galaxy appears to have a normal optical luminosity and
blue color (B-R = about 0.7) despite being one of the most luminous
galaxies known in the IR. Radio emission in the system is extended on
one side on a scale similar to the optical tails, but shows no detailed
correspondence with optical structure; in particular, there is no radio
counterpart to the optical 'jet'. Examination of IUE archival data
indicates that the UV flux is very weak and the UV spectrum is peculiar
for a Seyfert galaxy. The UV observations provide evidence for
considerable nuclear extinction in the system, in accordance with
previously published optical and IR work, but the UV extinction is
unlike Galactic absorption and may be more similar to that seen in the
LMC. Recent optical spectra of Mkn 231 show changes in both the
emission-line spectrum and in the strong broad absorption lines (BAL),
compared with previously published observations. It is suggested that
Mkn 231 may be a recently merged system which is currently undergoing
star formation. The connection with BAL QSOs is also discussed.
| Title: |
| Morphology and spectroscopy of Markarian 231. |
| Authors: |
| HUTCHINGS, J. B.; NEFF, S. G. |
| Journal: |
| Proceedings of the 121st symposium of the IAU held in Byurakan, Armenia, USSR, june 3-7, 1986 Ed. by Khachikian E.Y., Fricke K.J., Melnick J., 399-401 (1987) |
| Publication Date: |
| 00/1987 |
| Origin: |
| SIMBAD |
| Bibliographic Code: |
| 1987IAUS..121..399H |
Abstract
Not Available
| Title: |
| Sub-arc-second 10 mu.m observations of the Seyfert galaxy Mrk 231. |
| Authors: |
| NEUGEBAUER, G.; MATTHEWS, K.; MCGILL, J.; SOIFER, B. T. |
| Journal: |
| Bull. American Astron. Soc., 18, 1001 (1986) |
| Publication Date: |
| 00/1986 |
| Origin: |
| SIMBAD |
| Bibliographic Code: |
| 1986BAAS...18.1001N |
Abstract
Not Available
| Title: |
| ERRATUM - THE OPTICAL VARIABILITY OF TWO SEYFERT GALAXIES - ARAKELIAN:120 AND MARKARIAN:231 |
| Authors: |
| MILLER, H.R. |
| Journal: |
| ASTRON. AND ASTROPHYS. SUPPL. V.59, NO. 2/FEB, P. 367, 1985 |
| Publication Date: |
| 02/1985 |
| Origin: |
| KNUDSEN |
| Bibliographic Code: |
| 1985A&AS...59..367M |
Abstract
Not Available
| Title: |
| Echelle spectroscopy of the Seyfert 1 galaxy Markarian 231 |
| Authors: |
| RUDY, R. J.; STOCKE, J. T.; FOLTZ, C. B. |
| Affiliation: |
| AB(Steward Observatory, Tucson, AZ) AC(Steward Observatory, Tucson, AZ; Illinois, University, Urbana, IL) |
| Journal: |
| Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 288, Jan. 15, 1985, p. 531-534. Research supported by the University of Illinois. |
| Publication Date: |
| 01/1985 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTRONOMICAL SPECTROSCOPY, D LINES, SEYFERT GALAXIES, ABSORPTION SPECTRA, EMISSION SPECTRA, HYDROGEN, SPIRAL GALAXIES |
| Bibliographic Code: |
| 1985ApJ...288..531R |
Abstract
High-resolution (about 10 km/s) echelle spectroscopy of the sodium D
lines of absorption-line systems I and II, present in the spectrum of
the Seyfert 1 galaxy Markarian 231, is presented. The features show the
shape, displacement, and extent in velocity space characteristics of
broad absorption-line QSOs (BAL QSOs). The nature of the absorption
features indicates that the BAL QSO mechanism which accelerates the gas
in high-luminosity objects is operating in Mrk 231. Since the host
galaxy of Mrk 231 is not highly inclined to the line of sight, the BAL
QSO phenomenon is not restricted solely to galaxies with edge-on
orientations. It is shown that the absorbing gas contains both H II
regions which give rise to the He I lambda 3889 feature and neutral
zones where the Na(0) and Ca(+) absorptions originate. From the He I,
Na(0), and Ca(+) absorptions, a density of about 1000, a column density
of about 10 to the 22nd, and a distance from the nucleus of more than
150 pc for that gas are calculated.
| Title: |
| The luminous host galaxy and anomalous Brackett-gamma line of Markarian 231 |
| Authors: |
| CUTRI, R. M.; RIEKE, G. H.; LEBOFSKY, M. J. |
| Affiliation: |
| AC(Steward Observatory, Tucson, AZ) |
| Journal: |
| Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 287, Dec. 15, 1984, p. 566-570. NSF-supported research. |
| Publication Date: |
| 12/1984 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTRONOMICAL SPECTROSCOPY, GALACTIC STRUCTURE, INFRARED ASTRONOMY, LUMINOSITY, SEYFERT GALAXIES, ELECTRON DENSITY (CONCENTRATION), ELLIPTICAL GALAXIES, FOURIER TRANSFORMATION, H ALPHA LINE, INFRARED SPECTRA, LYMAN SPECTRA, NEAR INFRARED RADIATION, STELLAR EVOLUTION |
| Bibliographic Code: |
| 1984ApJ...287..566C |
Abstract
New infrared observations have been made of the Seyfert galaxy Markarian
231. Multiaperture photometry reveals that the underlying galaxy is
extremely luminous, with M(K) = -24.7. This implies that the Seyfert
nucleus likely resides in a giant elliptical galaxy, or possibly in a
galaxy which is undergoing a massive starburst. The strengths of the
Paschen-alpha and Brackett-gamma lines of hydrogen have been measured
using Fourier transform spectroscopy. An anomalously large
Pa-alpha/Br-gamma ratio may imply that the electron density in the broad
line clouds in Mrk 231 is much higher than that typically quoted for the
broad-line regions of other active galaxies. The possible origin of the
exceptional activity and the unusual spectroscopic properties in the
nucleus of Mrk 231 are examined in the context of the nature of the host
galaxy.
| Title: |
| Dust in the nuclei of the Seyfert galaxies Markarian 231 and NGC 4151 |
| Authors: |
| JONES, B.; WORRALL, D. M.; RODRIGUEZ-ESPINOSA, J. M.; STEIN, W. A.; GILLETT, F. C. |
| Affiliation: |
| AA(Hawaii, University, Mauna Kea, HI; California, University, La Jolla, CA) AC(California, University, La Jolla, CA) AD(Minnesota, University, Minneapolis, MN) AE(Kitt Peak National Observatory, Tucson, AZ) |
| Journal: |
| Astronomical Society of the Pacific, Publications (ISSN 0004-6280), vol. 96, Sept. 1984, p. 692-698. NSF-supported research. |
| Publication Date: |
| 09/1984 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| COSMIC DUST, GALACTIC NUCLEI, INTERSTELLAR EXTINCTION, SEYFERT GALAXIES, H II REGIONS, INFRARED ASTRONOMY, INTERSTELLAR MATTER |
| Bibliographic Code: |
| 1984PASP...96..692J |
Abstract
Observations carried out with a 8-13 micron grating-spectrometer of Mrk
231 and NGC 4151 are reported. The Mrk 231 data can be fitted to various
thermal dust emission models or a single power law, with dust
extinction. In all the model fits, except for that of graphite and
silicon carbide grain emission, a component of silicate absorption of
optical depth of not more than 0.7 is required. Confirming published
work, the absorption being at the redshift of the low-redshift
absorption-line system is ruled out. The high values of silicate optical
depth absorption do not give ratios to the galaxy's visual extinction
which are comparable to those of galactic H II regions. Weak evidence
for a 10-micron absorption feature in NGC 4151 is also reported. This is
somewhat contrary to expectation, since the visual extinction of NGC
4151 is lower than that of Mrk 231, and since there is evidence to
support a nonthermal rather than thermal dust origin for the infrared
continuum emission.
| Title: |
| The unusual 8-13 micron spectrum of Markarian 231 |
| Authors: |
| BREGMAN, J. D.; WITTEBORN, F. C. |
| Affiliation: |
| AB(NASA, Ames Research Center, Astrophysical Experiments Branch, Moffett Field, CA) |
| Journal: |
| Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X), vol. 281, June 1, 1984, p. L17-L19. |
| Publication Date: |
| 06/1984 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTRONOMICAL SPECTROSCOPY, INFRARED ASTRONOMY, SEYFERT GALAXIES, INFRARED SPECTRA, RED SHIFT, SILICATES |
| Bibliographic Code: |
| 1984ApJ...281L..17B |
Abstract
An 8-13 micron spectrum was obtained of the Seyfert galaxy Markarian 231
with a spectral resolution of 0.22 micron per point. The spectrum is
unlike any previously published spectrum at these wavelengths. The
spectrum can be attributed to a combination of absorption and reemission
by crystalline silicates which must have formed under conditions quite
different from those in which silicates form in the Galaxy. Comparison
of the data with previously published data indicates that the infrared
emission is extended and not dominated by a bright central source.
| Title: |
| 8-13 micron spectrophotometry of galaxies. III - The silicate absorption in Markarian 231 |
| Authors: |
| ROCHE, P. F.; AITKEN, D. K.; WHITMORE, B. |
| Affiliation: |
| AB(University College, London, England; Royal Australian Air Force Academy, Melbourne, Australia) AC(University College, London, England) |
| Journal: |
| Royal Astronomical Society, Monthly Notices (ISSN 0035-8711), vol. 205, Oct. 1983, p. 21P-26P. Research supported by the Science and Engineering Research Council. |
| Publication Date: |
| 10/1983 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| INFRARED ABSORPTION, INFRARED ASTRONOMY, INTERSTELLAR EXTINCTION, SEYFERT GALAXIES, SILICATES, GALACTIC NUCLEI, INFRARED SPECTRA, INTERSTELLAR MATTER, RED SHIFT, SPECTROPHOTOMETRY |
| Bibliographic Code: |
| 1983MNRAS.205P..21R |
Abstract
Spectrophotometry at 8-13 micron of Mkn 231 confirms that the 10 micron
minimum is due to large columns of silicate dust in the line-of-sight to
the nucleus. Fits to the detailed spectral shape demonstrate that the
cool absorbing grains are at the emission rather than the absorption
redshift and are located within the nuclear region.
| Title: |
| Optical polarization of the Seyfert galaxies Mrk 3, Mrk 231, NGC 3227 and NGC 3516 |
| Authors: |
| THOMPSON, I.; STOCKMAN, H. S.; ANGEL, J. R. P.; BEAVER, E. A. |
| Affiliation: |
| AC(Steward Observatory, Tucson, Ariz.) AD(California, University, La Jolla, Calif.) |
| Journal: |
| and J. D. Landstreet. Royal Astronomical Society, Monthly Notices, vol. 192, July 1980, p. 53-74. Research supported by the National Research Council of Canada |
| Publication Date: |
| 07/1980 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| EMISSION SPECTRA, GALACTIC STRUCTURE, LINE SPECTRA, OPTICAL POLARIZATION, SEYFERT GALAXIES, CIRCULAR POLARIZATION, CONTINUOUS SPECTRA, GALACTIC NUCLEI, H ALPHA LINE, INTERSTELLAR EXTINCTION |
| Bibliographic Code: |
| 1980MNRAS.192...53T |
Abstract
The paper presents intermediate resolution observations of the emission
line and continuum polarization of the Seyfert galaxies Mrk 3, Mrk 231,
NGC 3227, and NGC 3516. The polarization shows a strong wavelength
dependence with the polarization increasing smoothly into the blue for
each galaxy. This wavelength dependence, together with the presence of
polarized H(alpha) emission, indicates that the polarization of each
galaxy is caused by an asymmetric dust envelope surrounding the nucleus.
Observations of the polarization of the /O III/ lambda 5007 emission in
Mrk 3 and NGC 3227, and the polarization through the nonstellar Na ID
line absorption in Mrk 231 are used to place constraints on the extent
of the polarizing clouds in these galaxies. No polarization variability
was detected with time-bases ranging from a few weeks to three years.
| Title: |
| The optical variability of two Seyfert 1 galaxies - Arakelian 120 and Markarian 231 |
| Authors: |
| MILLER, H. R. |
| Affiliation: |
| AA(Georgia State University, Atlanta, Ga.) |
| Journal: |
| Astronomy and Astrophysics Supplement Series, vol. 35, Mar. 1979, p. 387-389. Research supported by the Research Corp. and Georgia State University. |
| Publication Date: |
| 03/1979 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTRONOMICAL PHOTOMETRY, GALACTIC RADIATION, SEYFERT GALAXIES, VARIABILITY, FORBIDDEN TRANSITIONS, LUMINOUS INTENSITY, STELLAR MAGNITUDE |
| Bibliographic Code: |
| 1979A&AS...35..387M |
Abstract
Not Available
| Title: |
| Substructure with Strong UV Excess in the Seyfert-Type Galaxy Markarian 231 |
| Authors: |
| KODAIRA, K.; LYE, M.; NISHIMURA, S. |
| Journal: |
| Publications of the Astronomical Society of Japan, Vol. 31, p. 451-460 (1979) |
| Publication Date: |
| 00/1979 |
| Origin: |
| OCR |
| Bibliographic Code: |
| 1979PASJ...31..451K |
Abstract
Not Available.
| Title: |
| The infrared polarization of NGC 1275, NGC 4151, Markarian 231, and 3C 273 |
| Authors: |
| KEMP, J. C.; RIEKE, G. H.; LEBOFSKY, M. J.; COYNE, G. V. |
| Affiliation: |
| AA(Oregon, University, Eugene, Ore.) AD(Steward Observatory; Arizona, University, Tucson, Ariz.) |
| Journal: |
| Astrophysical Journal, Part 2 - Letters to the Editor, vol. 215, Aug. 1, 1977, p. L107-L110. NSF-supported research. |
| Publication Date: |
| 08/1977 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| INFRARED RADIATION, POLARIZATION CHARACTERISTICS, QUASARS, SEYFERT GALAXIES, INFRARED ASTRONOMY, LIGHT MODULATION, OPTICAL POLARIZATION, PHOTOELASTICITY, POLARIMETRY |
| Bibliographic Code: |
| 1977ApJ...215L.107K |
Abstract
The letter reports initial observations obtained with an infrared
polarimeter employing photoelastic modulators. Operable over the range
from 1 to 8 microns, it has vanishing instrumental polarization, no more
than about 0.03% as verified so far. The common and surprising feature
of the four objects studied is the very small polarization at 2.2
microns, namely: (0.33 + or - 0.14)% in 3C 273, (0.13 + or - 0.06)% in
NGC 4151, (0.55 + or - 0.11)% in Markarian 231, and (0.52 + or - 0.20)%
in NGC 1275. These contrast with the large infrared polarizations in,
for example, BL Lacertae objects. At least in NGC 4151, if the radiation
mechanism is nonthermal it must be of an unpolarized type.
| Title: |
| The remarkable Seyfert galaxy Markarian 231 |
| Authors: |
| BOKSENBERG, A.; CARSWELL, R. F.; ALLEN, D. A.; FOSBURY, R. A. E.; PENSTON, M. V.; SARGENT, W. L. W. |
| Affiliation: |
| AB(University College, London, England) AE(Royal Greenwich Observatory, Herstmonceux, Sussex, England; Anglo-Australian Observatory, Epping, New South Wales, Australia) AF(Hale Observatories, Pasadena, Calif.) |
| Journal: |
| Royal Astronomical Society, Monthly Notices, vol. 178, Feb. 1977, p. 451-466. Research supported by the Smithsonian Research Foundation. |
| Publication Date: |
| 02/1977 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ABSORPTION SPECTRA, ASTRONOMICAL SPECTROSCOPY, EMISSION SPECTRA, LUMINOUS INTENSITY, QUASARS, SEYFERT GALAXIES, ASTRONOMICAL MODELS, BALMER SERIES, ELECTRONOGRAPHY, FLUORESCENCE, GALACTIC NUCLEI, H LINES, HOT STARS, K LINES, OPTICAL THICKNESS, RADIANT FLUX DENSITY, RED SHIFT, SPECTRUM ANALYSIS, STELLAR SPECTROPHOTOMETRY |
| Bibliographic Code: |
| 1977MNRAS.178..451B |
Abstract
Microdensitometer scans, spectrophotometric scans, spectra, and a direct
electronograph of the Seyfert galaxy Markarian 231 are presented and
analyzed. It is shown that the continuum of this galaxy is remarkably
red for a Seyfert and can be fitted with either a synchrotron spectrum
or the spectrum of a 10,000-K black body reddened by about 2.1
magnitudes. In either case, the absolute visual magnitude of the galaxy
is -25.1, the optical luminosity of many quasars. The emission-line
spectrum is synthesized from the H I, He I, Fe II, and forbidden O II
lines; the Balmer lines, other emission lines, and three systems of
absorption lines are also examined. The role of fluorescence in the line
emission is investigated, and two models for the nuclear region are
considered. In one model the continuum arises from hot stars, in the
other it is produced by a nonthermal source. It is concluded that
Markarian 231 is an extreme object since no sharp forbidden line
emission other than O II is observed, that all Lyman continuum photons
may be absorbed in the dense inner region, and that the high luminosity
of this galaxy places it in the quasar class.
| Title: |
| THE INFRARED EMISSION OF MARKARIAN 231 |
| Authors: |
| RIEKE, G. H. |
| Journal: |
| Astrophysical Journal Letters v.210, p.L5 |
| Publication Date: |
| 11/1976 |
| Origin: |
| OCR |
| Bibliographic Code: |
| 1976ApJ...210L...5R |
Abstract
Not Available
| Title: |
| Further infrared and millimeter observations of Markarian 231 |
| Authors: |
| JOYCE, R. R.; KNACKE, R. F.; SIMON, M.; YOUNG, E. |
| Journal: |
| Astronomical Society of the Pacific, Publications, vol. 87, Oct. 1975, p. 683-687. |
| Publication Date: |
| 10/1975 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| GALACTIC STRUCTURE, INFRARED ASTRONOMY, MILLIMETER WAVES, SEYFERT GALAXIES, THERMAL EMISSION, ASTRONOMICAL MODELS, MICROWAVE EMISSION, RADIO ASTRONOMY |
| Bibliographic Code: |
| 1975PASP...87..683J |
Abstract
New infrared and 3.3 millimeter observations of the Seyfert galaxy,
Markarian 231, are reported. Thermal and nonthermal models of the
radiation source are discussed although it is not possible to specify a
unique model based on these data.
| Title: |
| The aborption-line Seyfert galaxy Markarian 231. |
| Authors: |
| ADAMS, T. F.; WEEDMAN, D. W. |
| Journal: |
| Astrophys. J., 173, L109-L111 (1972) |
| Publication Date: |
| 05/1972 |
| Origin: |
| SIMBAD |
| Bibliographic Code: |
| 1972ApJ...173L.109A |
Abstract
Not Available
| Title: |
| First Results from the ISO-IRAS Faint Galaxy Survey |
| Authors: |
| LEVINE, DEBORAH A.; LONSDALE, CAROL J.; HURT, ROBERT L.; SMITH, HARDING E.; HELOU, GEORGE; BEICHMAN, CHARLES; CESARSKY, CATHERINE; ELBAZ, DAVID; KLAAS, ULRICH; LAUREIJS, RENE; LEMKE, DETRICH; LORD, STEVEN; MCMAHON, RICHARD; MOSHIR, MEHRDAD; NEUGEBAUER, GERRY; SOIFER, B. T.; VAN BUREN, DAVE; WEHRLE, ANN; WOLSTENCROFT, RAY |
| Journal: |
| Astrophysical Journal v.504, p.64 |
| Publication Date: |
| 09/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: PHOTOMETRY, INFRARED: GALAXIES, SURVEYS |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...504...64L |
Abstract
We present the first results from the ISO-IRAS Faint Galaxy Survey
(IIFGS), a program designed to obtain ISO observations of the most
distant and luminous galaxies in the IRAS Faint Source Survey by filling
short gaps in the ISO observing schedule with pairs of 12 mu m ISOCAM
and 90 mu m ISOPHOT observations. As of 1997 October, over 500 sources
have been observed, with an ISOCAM detection rate over 80%, covering
over 1.25 deg2 of sky to an 11.5 mu m point-source completeness limit of
approximately 1.0 mJy (corresponding to a ~10 sigma detection
sensitivity). Observations are presented for nine sources detected by
ISOPHOT and ISOCAM early in the survey for which we have ground-based G-
and I-band images and optical spectroscopy. The ground-based data
confirm that the IIFGS strategy efficiently detects moderate-redshift (z
= 0.11-0.38 for this small sample) strong emission line galaxies with
L60 mu m >~ 1011 L&sun; one of our sample has L60 mu m > 1012 L&sun; (H0
= 75 km s-1 Mpc-1, Omega = 1). The infrared-optical spectral energy
distributions are comparable to those of nearby luminous infrared
galaxies, which span the range from pure starburst (e.g., Arp 220) to
infrared QSO (Mrk 231). Two of the systems show signs of strong
interaction, and four show active galactic nucleus (AGN)-like
excitation; one of the AGNs, F15390+6038, which shows a high excitation
Seyfert 2 spectrum, has an unusually warm far- to mid-infrared color and
may be an obscured QSO. The IIFGS sample is one of the largest and
deepest samples of infrared-luminous galaxies available, promising to be
a rich sample for studying infrared-luminous galaxies up to z ~ 1 and
for understanding the evolution of infrared galaxies and the star
formation rate in the universe.
| Title: |
| Adaptive optics observations of ultra-luminous infrared galaxies I. J, H, K images of Mkn 231 |
| Authors: |
| LAI, O.; ROUAN, D.; RIGAUT, F.; ARSENAULT, R.; GENDRON, E. |
| Affiliation: |
| AA(Observatoire de Paris-Meudon, Departement Spatial, CNRS, F-92195 Meudon Cedex, France (lai@hplyot.obspm.fr)), AB(Observatoire de Paris-Meudon, Departement Spatial, CNRS, F-92195 Meudon Cedex, France (lai@hplyot.obspm.fr)), AC(Canada-France-Hawaii Telescope Corp.), AD(Canada-France-Hawaii Telescope Corp.), AE(Observatoire de Paris-Meudon, Departement Spatial, CNRS, F-92195 Meudon Cedex, France (lai@hplyot.obspm.fr)) |
| Journal: |
| Astronomy and Astrophysics, v.334, p.783-788 (1998) |
| Publication Date: |
| 06/1998 |
| Origin: |
| A&A |
| A&A Keywords: |
| ADAPTIVE OPTICS, INFRARED: GALAXIES, , GALAXIES: STARBURST, GALAXIES: SEYFERT, GALAXIES: INDIVIDUAL: MKN 231 |
| Abstract Copyright: |
| (c) 1998: Astronomy & Astrophysics |
| Bibliographic Code: |
| 1998A&A...334..783L |
Abstract
We present adaptive optics observations in J, H and K of the
Ultra-Luminous Infrared Galaxy, Markarian 231. This galaxy is the one
among ULIRGs that shows most clearly the character of a QSO with a very
peaked nuclear source. Even with a FWHM PSF of 0.11 arcsec, our images
show that the central source is still unresolved and should be more
compact than 50 pc; in addition, the position on the [J-H]/[H-K]
color-diagram of this point-like source is very close to the locus of
QSOs. Both results point to an actual AGN - almost unreddened - at the
center of Mkn 231. The underlying extended emission appears to be
extremely red in a circum-nuclear region of ~ 2.5 kpc, that should be
identified with the hot molecular gas disk recently found in H_2. In
addition, we detect on the deconvolved images a second source (B) at
0.15 arcsec north to the nucleus with [H-K] colors that are consistent
either with the stellar nucleus of a merging galaxy, or with a giant HII
complex of violent star formation. We favor the later interpretation
since this source lies in the direction where the molecular hydrogen
emission peaks.
Based on observations obtained at Canada-France-Hawaii Telescope
operated by the National Research Council of Canada, The Centre National
de la Recherche Scientifique de France and the University of Hawaii.
Abstract
We have used the UCSD/Keck Long Wavelength Spectrometer (LWS; Jones &
Puetter 1993, Proc. S.P.I.E., 1946, 610) in its initial (72 x 64)
imaging mode to observe the luminous IR Galaxies Mrk 231, Arp 220, and
NGC 7469, as well as NGC 1068 at mid-infrared wavelengths from
8--18\micron. Pixon-based image reconstruction techniques (Puetter 1995,
Int. J. Image Sys. & Tech., 6, 314) have been employed to achieve
resolution as high as 50 mas. The mid-infrared emission in Arp 220 is
resolved into the two nuclei plus a faint knot of emission 0.5 arcsec SE
of the western nucleus. The SEDs show that the the W nucleus dominates
at the longest wavelengths and probably in the far-infrared. Silicate
absorption at 10\micron\ is present in all three components, but is
strongest in the E nucleus, suggesting that the emission comes from an
optically thick shell around a very compact mid-IR source. The E nucleus
is unresolved at 0.2 arcsec resolution. The nucleus of NGC 7469 is
marginally resolved at 50mas resolution. On the average the nuclear
emission is redder than the surrounding starburst ring; the active
nucleus dominates at all mid-infrared wavelengths and the ratio of
Nucleus/Starburst increases toward the FIR. Mrk 231 shows a compact,
unresolved nucleus with a faint, resolved star-formation ring. These
observations will be discussed in terms of the Sanders et al. (1988,
ApJ, 325 74) model in which LIGs evolve from Starbursts to AGN.
The LWS is being upgraded with a Boeing 128 x 128 BIB array which is
expected to be delivered in early summer. A 128 x 128 element
multiplexer has been installed and optical performance reverified;
further temperature stability tests and signal-to-noise optimization are
being performed with an engineering array. The upgraded spectrometer
with 11" FOV for imaging and spectroscopic resolutions, R=100 and 1000,
is expected to be recommissioned this summer and to be available for
scheduling in second semester 1998.
| Title: |
| SN1987C in Mrk 90 = UGC 4438: Evolution of a Type "IIn" to a Type IIP? |
| Authors: |
| SCHLEGEL, ERIC M.; KIRSHNER, ROBERT P. |
| Affiliation: |
| Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA |
| Journal: |
| New Astronomy, vol. 3, no. 2, p. 125-136. |
| Publication Date: |
| 01/1998 |
| Origin: |
| NEWA |
| Objects: |
| NGC 1035; SN1969L; SN1978K; SN1980K; SN1981K; SN1983N; SN1986J; SN1987A; SN1987B; SN1987C; SN1987F; SN1988A; SN1988Z; SN1990E; SN1992H; SN1993J; SN1994W; SN1996cn; UGC 4438 |
| Keywords: |
| SUPERNOVAE: INDIVIDUAL: SN1987C |
| Bibliographic Code: |
| 1998NewA....3..125S |
Abstract
We describe three optical spectra and four photometric observations of
SN1987C. The light curve is best described by a Type II-P template. The
first spectrum of SN1987C, at day 53, is similar to spectra of other
members of the "Type IIn" subclass. Spectra at 80 and 231 days appear
essentially identical to late-time spectra of normal Type II-P
supernovae. The data provide clues to suggest that at least this example
of a "IIn" object was a hidden Type II-P supernova during its early
evolution. We believe that we have observed the effects of a transition
from emission dominated by the kinetic energy of an expanding shell to
emission dominated by the radioactive decay of synthesized isotopes. As
far as we know, this is the first time such a transition has been
observed.
| Title: |
| The Starburst-AGN Connection. II. The Nature of Luminous Infrared Galaxies as Revealed by VLBI, VLA, Infrared, and Optical Observations |
| Authors: |
| SMITH, HARDING E.; LONSDALE, COLIN J.; LONSDALE, CAROL J. |
| Journal: |
| Astrophysical Journal v.492, p.137 |
| Publication Date: |
| 01/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: STARBURST, RADIO CONTINUUM: GALAXIES |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...492..137S |
Abstract
We present here detailed results of an 18 cm VLBI survey of 31 luminous
(LFIR > 1011.25 L&sun;), radio-compact ( theta <~ 0."25) infrared
galaxies (LIGs). High-resolution VLA maps at 15 and 22 GHz are presented
for 14 of these galaxies that exhibit compact milliarcsecond-scale
emission, providing information about radio structure of LIGs on scales
from 0."004 to 1."0. We also present new optical spectrophotometric
observations. Over half the sample galaxies show high brightness
temperature radio emission from the VLBI data, with Tb > 105 K and
structure on scales of 5-150 mas, as previously reported in Lonsdale,
Smith, & Lonsdale. The median VLBI power for detected sources is log
PVLBI = 22.0 (W Hz-1), and the mean ratio of VLBI to total 1.6 GHz flux
density is <SVLBI/Stotal> = 0.12. Further structure is observed on the
larger VLA scales. No highly significant (P < 1%) statistical
correlations are found between the presence or strength of the VLBI
emission and other observed quantities, including total radio power,
radio spectral index, IR luminosity and colors, radio-infrared ratio,
molecular gas mass, and optical excitation. Statistical analysis does
suggest that the infrared luminosity, molecular gas emission, and radio
emission on VLA and VLBI scales are physically related. Previous work
(Lonsdale, Smith, & Lonsdale) demonstrated that hidden (dust-enshrouded)
active galactic nuclei (AGNs) are capable of powering LIGs and giving
rise to the observed VLBI- and VLA-scale structures; here we investigate
the complementary question of whether a starburst can completely explain
the observed characteristics, including the high brightness temperature
radio emission. Simple starburst models show that the far-infrared
luminosity can be explained by starbursts in all cases except Mrk 231,
although for some objects the constraints imposed on the initial mass
function are severe. Using our starburst models we model the VLBI data
for 11 galaxies with detailed radio structural information using
complexes of radio supernovae. The required supernova rates are nu sn ~
0.1-2 yr-1, consistent with the rates derived from the starburst model
to explain the observed far-infrared luminosities. However in all cases
we require complexes of extremely luminous radio supernovae (RSNs) to
explain the high-Tb emission. In some cases the RSN must have
implausibly high radio powers, more than an order of magnitude larger
than any previously reported RSNs; in our view these sources represent
AGN radio cores. In most cases an acceptable fit requires that the RSN
be clustered on parsec scales. Furthermore, only a few clumps may be
active in the radio at a given time. Based on this analysis we conclude
that 7/11 systems can be plausibly explained as starbursts. Four
galaxies, UGC 2369, Mrk 231, UGC 5101, and NGC 7469, almost certainly
house AGN radio cores. From our modeling, coupled with other recent VLBI
and infrared evidence, we conclude that Arp 220 is dominated by a
massive starburst at radio and infrared wavelengths.
| Title: |
| Keck Mid-IR Imaging of Luminous Infrared Galaxies: Starbursts & AGN |
| Authors: |
| SMITH, H. E.; JONES, B.; PUETTER, R. C.; STEIN, W. A.; WANG, M. C.; CAMPBELL, R. |
| Affiliation: |
| AA(CASS/UCSD), AF(Keck Obs.) |
| Journal: |
| American Astronomical Society Meeting, 191, #76.16 |
| Publication Date: |
| 12/1997 |
| Origin: |
| AAS |
| Abstract Copyright: |
| (c) 1997: American Astronomical Society |
| Bibliographic Code: |
| 1997AAS...191.7616S |
Abstract
We have obtained 8--18microns images of the Luminous Infrared Galaxies
(LIGs) Mrk 231, Arp 220 & NGC 7469 with the UCSD Long Wavelength Imaging
Spectrometer (LWS; and Puetter, 1993, Proc. S.P.I.E., 1946, pp. 610-621)
on the W. M. Keck Telescope. Pixon-based image reconstruction
techniques (Puetter, 1995, Int. J. Image Sys. & Tech., 6, pp. 314-331)
have been employed to achieve sub-diffraction limited resolution ( ~
50mas). The twin nuclei of Arp 220 are clearly distinguished in the raw
data. The mid-infrared flux-density ratios of the two nuclei, compared
with data from the near-infrared (Graham, et al 1990, ApJL, 354, L5) and
VLBI images (Smith, Lonsdale, Diamond & Lonsdale, 1997, ApJL, in press)
suggest that star formation is actively continuing in the Western
nucleus while activity in the Eastern nucleus has decreased
significantly, although the histories of the two nuclei may have been
similar.
Our images of the Sy 1 galaxy NGC 7469 clearly show the star-formation
ring surrounding the Seyfert nucleus. Comparison will be made between
our mid-infrared images and the 3.6cm radio data (Condon, et al. 1991,
ApJ, 378, 65). The nucleus is marginally resolved at 50mas resolution,
implying a physical size of about 15pc, comparable to the size of the
compact VLBI core (Lonsdale, Smith & Lonsdale 1995, BAAS, 38, 1359) and
suggesting that the active nucleus and warm-dust emitting region may be
physically related.
The three galaxies represent a sequence from dominant Starburst (Arp
220) to AGN (Mrk 231); speculations for LIG evolution will be briefly
discussed.
This work has been supported by the NSF, NASA, CARA and the W. M. Keck
Foundation, to whom we express our thanks.
| Title: |
| Circumnuclear molecular gas and star formation in starburst galaxies. |
| Authors: |
| PLANESAS, P.; COLINA, L.; PEREZ-OLEA, D. |
| Journal: |
| Astronomy and Astrophysics, v.325, p.81-97 |
| Publication Date: |
| 09/1997 |
| Origin: |
| A&A via CDS |
| A&A Keywords: |
| GALAXIES: GENERAL, GALAXIES: ISM, GALAXIES: SEYFERT, GALAXIES: STARBURST |
| Abstract Copyright: |
| (c) 1997: Astronomy & Astrophysics |
| Bibliographic Code: |
| 1997A&A...325...81P |
Abstract
The molecular gas properties and circumnuclear star formation in the
nearby nuclear starburst galaxies NGC 2903, NGC 3351 and NGC 3504 are
investigated in detail. The circumnuclear HII regions in the
star-forming rings of these galaxies are characterised by an ionized gas
mass in the 10^4^-10^5^M_{sun}_ range, and by an ionizing flux in the
10^51^-10^52^ph/s range, typical of giant HII regions in external
galaxies. The CO 2->1 emission in NGC 3504 indicates the presence of two
emitting regions separated by 115km/s in velocity and 5" (500pc)
spatially, what approximately corresponds to the location of the the
inner inner Lindblad resonance. The measured (CO 2->1)/(CO 1->0)
integrated intensity ratio for the inner kpc of NGC 3351 is 0.8, in
agreement with the empirical average value found for spiral galaxies
with a normal metallicity regardless of the presence or the absence of a
starburst. Molecular gas masses in the range of
M_H_2__=~10^8^-10^9^M_{sun}_ are measured in regions of a few hundred
parsecs in size. On average, the circumnuclear region of the three
galaxies is characterised by an average molecular gas surface density
{SIGMA}_H_2__=280M_{sun}_/pc^2^, and average
L_IR_/M_H_2__=21L_{sun}_/M_{sun}_. The L_IR_/M_H_2__-{SIGMA}_H_2__
relationship covering the {SIGMA}_H_2__ range from normal spiral
galaxies and giant molecular clouds in the Milky Way with
{SIGMA}_H_2__~10^1^-10^2^M_{sun}_/pc^2^, to nearby starbursts, AGNs
with starbursts, and luminous IRAS galaxies with
{SIGMA}_H_2__~2x10^2^-10^5^M_{sun}_/pc^2^, is investigated. Nearby
starburst galaxies have an average molecular gas surface density
{SIGMA}_H_2__ of 400M_{sun}_/pc^2^ and an average L_IR_/M_H_2__ of
23L_{sun}_/M_{sun}_. These two properties are explained by the existence
of giant molecular clouds with associated HII regions where the star
formation process is characterised by being short lived
(<=3x10^7^years), biased towards a high lower mass limit M_l_~3M_{sun}_,
and with an overall gas to stars conversion fraction of <=10% of the gas
mass. The star formation efficiency (SFE) in nearby starbursts and
luminous IRAS galaxies (as measured by the L_IR_/M_H_2__ ratio) does not
show any indication of a linear correlation with increasing
{SIGMA}_H_2__. On the contrary, the star formation efficiency is
restricted to the 10<L_IR_/M_H_2__<100L_{sun}_/M_{sun}_ range, and
reaches a maximum value of L_IR_/M_H_2__=100L_{sun}_/M_{sun}_ for
{SIGMA}_H_2__ larger than 10^3^M_{sun}_/pc^2^. The upper limit found for
the L_IR_/M_H_2__ ratio, independent of {SIGMA}_H_2__, implies the
existence of an upper limit in the fraction of gas converted into stars
independent of the density. The SFE range observed in nearby starbursts,
Seyferts with starbursts, and luminous IRAS galaxies is explained as a
combination of massive star formation in the circumnuclear regions of
these galaxies plus the additional contribution of an AGN at the center
of the galaxy. Under the starburst+AGN scenario, most of the molecular
gas mass is directly involved in the star forming process while the AGN
contribution to the global IR luminosity is in the 10% to 75% range,
depending on the galaxy. In this scenario, the infrared luminosity of
galaxies with observed L_IR_/M_H_2__ ratio in the 10 to
30L_{sun}_/M_{sun}_ range is dominated by the circumnuclear star
formation alone. The infrared luminosity in those galaxies with
L_IR_/M_H_2__ in the 30-100L_{sun}_/M_{sun}_ range is increasingly
dominated by the central AGN. Examples of this situation are NGC 1068,
NGC 7469 and Mrk 231.
| Title: |
| Arcsecond Imaging of CO Emission in the Nucleus of Arp 220 |
| Authors: |
| SCOVILLE, N. Z.; YUN, M. S.; BRYANT, P. M. |
| Journal: |
| Astrophysical Journal v.484, p.702 |
| Publication Date: |
| 07/1997 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: INDIVIDUAL NAME: ARP 220, GALAXIES: INTERACTIONS, GALAXIES: ISM |
| Abstract Copyright: |
| (c) 1997: The American Astronomical Society |
| Bibliographic Code: |
| 1997ApJ...484..702S |
Abstract
We report high-resolution (1") imaging of CO (2--1) and dust continuum
emission in the ultraluminous galaxy Arp 220. The CO (1--0) line was
also imaged at 2" resolution for comparison. Both data sets recover
essentially all of the observed single-dish line emission. Our aperture
synthesis maps reveal for the first time, multiple components in the
dense gas: peaks corresponding to each of the double nuclei (separated
by 0."95 at P.A. = 101 deg) seen in the near infrared and radio
continuum and a more extended disklike structure at P.A. = 53 deg,
similar to the dust lane seen in optical images. Approximately
two-thirds of the total CO emission (and presumably the H2 mass)
coincides with the compact double nucleus region. The ISM associated
with these nuclear sources is most apparent in the 1.3 mm dust continuum
emission, but the brightest CO (2--1) emission is also correlated with
the near infrared nuclei and exhibits a radial velocity difference of
250--300 km s-1 between the two nuclei. The latter is in excellent
agreement with published near-infrared recombination line measurements.
The observed velocity difference between the two nuclei is probably much
less than their orbital velocity because the nuclei do not lie along the
kinematic major axis of the inner disk. The elongated disk feature
exhibits a monotonic velocity gradient parallel to the major axis of the
CO intensity distribution with the highest receding velocities in the
southwest and the highest approach velocities in the northeast. From the
major/minor axis ratio (0.66), we infer that the disk is moderately
inclined to the line of sight (i = 40--50 deg). Detailed modeling of the
CO line profiles using a Doppler image-deconvolution technique,
analogous to Doppler radar imaging, yields a best-fit CO emissivity
distribution and rotation curve which are mutually consistent in the
sense that if the total mass distribution follows the CO emissivity,
then it yields the derived rotation curve. The implied CO-to-H2
conversion ratio is 0.45 times the Galactic value if the bulk of the
mass resides in the molecular gas, rather than stars. This value is also
consistent with that expected based on the likely molecular density and
temperature in the nuclear disk of Arp 220. The total molecular gas mass
for Arp 220 is ~9 x 109 M&sun; with an uncertainty of ~30% based on the
line profile modeling. The peak gas surface density is ~5.8 x 104 M&sun;
pc-2 at 130 pc radius, while the two stellar nuclei are at ~235 pc
radius and at position angle midway between the major and minor axes of
the gaseous disk. From the profile modeling we derive an intrinsic
velocity dispersion in the disk of 90 +/- 20 km s-1 and thus a disk
thickness (FWHM) of only 16 pc, assuming the disk is in hydrostatic
equilibrium. With 5.4 x 109 M&sun; of molecular gas concentrated in the
very thin disk associated with the twin nuclei, the mean density will be
n_{{H}_{2}} ~= 2 x 104 cm-3 (+/-30%), a value which is consistent with
the strong molecular emission from high dipole moment molecules such as
HCN and HCO+. From the high brightness temperatures of the observed CO
emission (17--21 K), we conclude that the area filling factor of the
disk is very high (~=0.25) and therefore the gas must fairly uniformly
fill the disk, rather than being in discrete self-gravitating clouds.
This thin central disk will have inward accretion at ~=100 M&sun; yr-1
due to viscous and spiral arm transfer of angular momentum. The line
profiles at the positions of the double nuclei are double peaked
suggesting that there may also be less massive accretion disks
associated with each nucleus. The fact that the bulk of the molecular
gas has relaxed into a disk with large masses of gas concentrated
interior to the double nuclei is consistent with scenarios in which the
gas in merging systems settles into the center faster than the two
stellar/starburst nuclei. We suggest that dense central accretion disks
like that in Arp 220 may be a common feature in the evolution of
ultraluminous starburst/AGN galaxies since similar qualitative features
are seen in the molecular line data for other systems (e.g., Mrk 231 and
NGC 6240).
| Title: |
| X-ray and optical continua of active galactic nuclei with extreme Fe II emission |
| Authors: |
| LAWRENCE, A.; ELVIS, M.; WILKES, B. J.; MCHARDY, I.; BRANDT, N. |
| Affiliation: |
| AA(Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ ), AB(Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, USA ), AC(Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, USA ), AD(Physics Department, Southampton University, University Road, Southampton SO9 5NH ), AE(Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA ) |
| Journal: |
| Monthly Notices of the Royal Astronomical Society, Volume 285, Issue 4, pp. 879-890. |
| Publication Date: |
| 03/1997 |
| Origin: |
| MNRAS |
| MNRAS Keywords: |
| GALAXIES: ACTIVE, GALAXIES: NUCLEI, QUASARS: EMISSION LINES, X-RAYS: GALAXIES |
| Abstract Copyright: |
| (c) 1997 The Royal Astronomical Society |
| Bibliographic Code: |
| 1997MNRAS.285..879L |
Abstract
We present the results of ROSAT PSPC observations of three active
galactic nuclei (AGN) with extremely strong FeII emission (PHL 1092,
IRAS 07598+6508 and IZw1) and two AGN with very weak FeII emission (Mrk
10 and 110). The weak FeII emitters have X-ray spectra typical of Type 1
AGN (alpha=1.35 and 1.41, where alpha is the spectral energy index). Of
the strong FeII emitters, two have steep spectra (PHL 1092 has
alpha=3.5, and IZw1 has Upsilon=2.0) and the third, IRAS 07598+6508, is
barely detected and so is extremely X-ray-quiet (alpha_ox=2.45). During
our observations, PHL 1092 varied by a factor of 4, unusually fast for
such a high-luminosity object, and requiring an efficiency of
matter-to-energy conversion of 2 per cent or more. Compiling recently
published data on other strong FeII emitters, we find that they are
always X- ray-quiet, and usually X-ray-steep. Adding these data to the
complete UVX-selected quasar sample of Laor et al., we find a
statistical connection of FeII/Hbeta with alpha_x but not a simple
relationship: weak FeII emitters always have flat spectra, but strong
FeII emitters can be either flat or steep. A much cleaner relationship
exists between FeII strength and X-ray loudness, as quantified by
alpha_ix, the spectral index between 1mum and 2keV. We also confirm that
FeII/Hbeta anticorrelates with Balmer line velocity width, which in turn
correlates well with both alpha_x and alpha_ix in the sense that AGN
with narrow lines are X-ray-quiet. There is also marginal evidence that
FeII/Hbeta correlates with both optical continuum slope and the
curvature of the optical-UV-X-ray continuum: strong FeII objects tend to
have steeper continua and weaker `blue bumps'. The amount of extinction
required to explain the optical steepening compared to normal quasars
[E(B-V) in the range 0.2 to 0.6] suggests absorbing columns in the range
(1-3)x10^21 cm^-2, just about the right amount to reduce the ROSAT-band
X-ray flux by enough to explain the correlation with alpha_ix. However,
the spectral shapes observed in the ROSAT band are not consistent with a
simple absorption model. Three objects in our total sample of 19 stand
out persistently in all correlations: Mrk 231, IRAS 07598+6508 and Mrk
507. Interestingly, two out of the three are known to have
low-ionization, broad absorption lines in the UV, and the third (Mrk
507) has no UV spectrum available. Furthermore, low-ionization, broad
absorption lines are at least an order of magnitude more common in
strong FeII emitters than in quasars in general. Overall, continuum
shape and blueshifted absorption should be added to the intriguing
cluster of properties which all vary loosely together, and which has
been isolated as `eigenvector 1' by Boroson & Green: FeII strength,
velocity width, narrow-line strength and line asymmetry. We suggest that
the underlying parameter is the density of an outflowing wind.
| Title: |
| Hubble Space Telescope Ultraviolet Spectrum of Arp 102B, the Prototypical Double-peaked Emission-Line AGN |
| Authors: |
| HALPERN, JULES P.; ERACLEOUS, MICHAEL; FILIPPENKO, ALEXEI V.; CHEN, KAIYOU |
| Journal: |
| Astrophysical Journal v.464, p.704 |
| Publication Date: |
| 06/1996 |
| Origin: |
| APJ; NED |
| ApJ Keywords: |
| ACCRETION, ACCRETION DISKS, GALAXIES: ACTIVE, GALAXIES: NUCLEI, GALAXIES: INDIVIDUAL NAME: ARP 102B, GALAXIES: QUASARS: ABSORPTION LINES, LINE: PROFILES |
| Bibliographic Code: |
| 1996ApJ...464..704H |
Abstract
UV spectra of the nucleus of the elliptical galaxy Arp 102B were
obtained with the HST's Faint Object Spectrograph in order to
investigate the UV emission-line counterparts of its unusual
double-peaked Balmer lines. Broad Mg II {lambda}2798 is present with
nearly the same profile as the Balmer lines (peaks separated by ~12,000
km s^-1^), and a typical Mg II/H{beta} ratio of 1. But there is little,
if any C III] {lambda} 1909 or C IV {lambda}1550 emission corresponding
to the displaced Balmer- line peaks. Most important, there is no
double-peaked component detected in Ly{alpha}; the Ly{alpha}/H{beta}
ratio is less than 0.12 in the displaced peaks. However, there is an
"ordinary," nondisplaced broad-line component with FWHM ~3500 km s^-1^
in all of the permitted lines, demonstrating the need to invoke
different locations and different physical conditions for double-peaked
and single-peaked line components in the same object. The. striking
absence of displaced peaks In Ly{alpha} probably cannot be explained
solely by reddening. Rather, It indicates that high density and large
optical depth in Ly{alpha} are required to destroy the line photons by
collisional de-excitation and possibly by bound-free absorption out of
the n = 2 level of hydrogen. These results strongly support the
application, at least to Arp 102B, of the accretion- disk model of
Dumont & Collin-Souffrin, in which the disk produces only low-ionization
lines and a Ly{alpha}/H{beta} ratio that agrees with our observed upper
limit. Also present is an extraordinary system of absorption lines at
the systemic redshift of Arp 102B, in which metastable levels of Fe II
up to 1.1 eV above the ground state participate in addition to the more
common resonance transitions. Absorption from metastable levels of Fe II
have been seen previously only in two unusual, low-ionization broad
absorption-line QSOs, Q0059 - 2735 and Mrk 231. Temperatures and
densities needed to excite these levels are similar to narrow-line
region conditions. Why they are seen in absorption in Arp 102B, a
relatively unobscured active galactic nucleus, but in no other Seyfert
or radio galaxy, is a mystery.
| Title: |
| Multiwavelength energy distributions of ultraluminous IRAS galaxies - I. Submillimetre and X-ray observations |
| Authors: |
| RIGOPOULOU, DIMITRA; LAWRENCE, ANDY; ROWAN-ROBINSON, MICHAEL |
| Affiliation: |
| AA(Physics Department, Queen Mary and Westfield College, Mile End Road, London E1 4NS, UK ), AB(Physics Department, Queen Mary and Westfield College, Mile End Road, London E1 4NS, UK ), AC(Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BZ, UK ) |
| Journal: |
| Monthly Notices of the Royal Astronomical Society, Volume 278, Issue 4, pp. 1049-1068. |
| Publication Date: |
| 02/1996 |
| Origin: |
| MNRAS |
| MNRAS Keywords: |
| GALAXIES: ACTIVE, GALAXIES: SEYFERT, GALAXIES: STARBURST, RADIO CONTINUUM: GALAXIES, X-RAYS: GALAXIES |
| Abstract Copyright: |
| (c) 1996 The Royal Astronomical Society |
| Bibliographic Code: |
| 1996MNRAS.278.1049R |
Abstract
We present photometric observations at 350, 450, 800 and 1100 mum of
nine out of 10 ultraluminous IRAS galaxies from the BGS sample (Sanders
et al.), carried out with the JCMT telescope, and X-ray observations of
six of them, carried out with the ROSAT PSPC. Together with other
published and archived data the multiwavelength spectral energy
distributions for all the 10 galaxies of the sample, from radio out to
the X-rays, are constructed and discussed. Submillimetre observations
are consistent with a thermal origin of the energy output of these
systems in almost all cases, and in particular are well fitted by the
starburst model proposed by Rowan-Robinson & Efstathiou. The weak soft
X-ray emission excludes the possibility of the objects being quasars
with a modest line-of-sight reddening; however, the absorbing columns
expected from CO measurements are enough to obliterate soft X-rays
completely. There is evidence for two single-nucleus objects to be a
Seyfert 1 (Mrk 231) and a Seyfert 2 (IRAS 05189) galaxy respectively,
but even these objects are extremely X-ray-quiet. It is suggested that
in most objects starburst activity rather than accretion on to a massive
black hole is responsible for the tremendous amounts of energy released
from infrared galaxies with luminosities L_FIR<~10^12 L_solar.
| Title: |
| Molecular line CO (2->1) observations of ultraluminous IRAS galaxies. |
| Authors: |
| RIGOPOULOU, D.; LAWRENCE, A.; WHITE, G.J.; ROWAN-ROBINSON, M.; CHURCH, S.E. |
| Journal: |
| Astronomy and Astrophysics, v.305, p.747 |
| Publication Date: |
| 01/1996 |
| Origin: |
| A&A via CDS |
| A&A Keywords: |
| GALAXIES: ISM, GALAXIES: ACTIVE, RADIO LINES: GALAXIES |
| Abstract Copyright: |
| (c) 1996: Astronomy & Astrophysics |
| Bibliographic Code: |
| 1996A&A...305..747R |
Abstract
CO (J=2->1) observations of six ultraluminous IRAS galaxies are
presented. Four of these galaxies have no previous CO J=2->1 data and
two have no previous CO detections at all. Based on these observations,
molecular hydrogen masses are estimated and range from 5x10^9^ to
1.8x10^10^M_{sun}_. The present data follow the well established
correlation that exists between the infrared luminosity L_IR_ and the
molecular mass content. The high values of the L_IR_/M_H_2__ suggest
either an increased star formation efficiency and / or an additional
source of luminosity such as an active nucleus. The ratio
R=(J=2->1)/(J=1->0) between the J=2->1 and 1->0 line temperatures, is
examined next using our J=2->1 intensities and other published CO J=1->0
data. For Arp 220, Mrk 231, Mrk 273 R lies in the range 0.7 to 1.1; for
IRAS 05189 the CO intensity and the ratio R were both found to have
extremely low values. The low values of R<=1 found for all galaxies,
suggest that the line profiles are dominated by emission coming from
optically thick thermalized CO. Finally the line profiles are examined
and compared to published models concerning the distribution and
kinematics of the gas. Assuming that the CO is distributed in a disk as
in normal spiral galaxies, then this region is probably concentrated
towards the center of the galaxies.
| Title: |
| HST Ultraviolet Spectrum of Arp 102B, the Prototypical Double-Peaked Emission-Line AGN |
| Authors: |
| ERACLEOUS, M.; FILIPPENKO, A. V.; HALPERN, J. P.; CHEN, K. |
| Affiliation: |
| AA(UCB), AC(Columbia U.), AD(LANL) |
| Journal: |
| American Astronomical Society Meeting, 187, #56.07 |
| Publication Date: |
| 12/1995 |
| Origin: |
| AAS |
| Abstract Copyright: |
| (c) 1995: American Astronomical Society |
| Bibliographic Code: |
| 1995AAS...187.5607E |
Abstract
UV spectra of the nucleus of the elliptical galaxy Arp 102B were
obtained with the HST's Faint Object Spectrograph in order to
investigate the UV emission-line counterparts of its unusual
double-peaked Balmer lines. Broad Mg II lambda 2798 is present with
nearly the same profile as the Balmer lines (peaks separated by ~ 12,000
km s(-1) ), and a typical Mg II/Hbeta ratio of 1. But there is little,
if any C III] lambda 1909 or C IV lambda 1550 emission corresponding to
the displaced Balmer-line peaks. Most important, there is no
double-peaked component detected in Lyalpha ; the Lyalpha /Hbeta ratio
is < 0.12 in the displaced peaks. However, there is an ``ordinary,''
non-displaced broad-line component with FWHM ~ 3500 km s(-1) in all of
the permitted lines, demonstrating the need to invoke different
locations and different physical conditions for double-peaked and
single-peaked line components in the same object. The striking absence
of displaced peaks in Lyalpha cannot be explained solely by reddening.
Rather, it indicates that high density and large optical depth in
Lyalpha are required to destroy the line photons by collisional
deexcitation and possibly by bound-free absorption out of the n=2 level
of hydrogen. These results strongly support the application, at least
to Arp 102B, of the accretion-disk model of Dumont and Collin-Souffrin,
in which the disk produces only low-ionization lines and a Lyalpha
/Hbeta ratio that agrees with our upper limit.
Also present is an extraordinary system of absorption lines at the
systemic redshift of Arp 102B, in which metastable levels of Fe II up to
1.1 eV above the ground state participate in addition to the more common
resonance transitions. Absorption from metastable levels has been seen
previously only in two unusual, low-ionization BALQSOs, Q0059--2735 and
Mrk 231. Why they are seen in absorption in Arp 102B, a relatively
unobscured AGN, but in no other appropriately observed Seyfert or radio
galaxy, is a mystery.
| Title: |
| An Extended Molecular Gas Distribution in Markarian 273 and Merger-Luminosity Evolution |
| Authors: |
| YUN, M. S.; SCOVILLE, N. Z. |
| Journal: |
| Astrophysical Journal Letters v.451, p.L45 |
| Publication Date: |
| 10/1995 |
| Origin: |
| APJ; KNUDSEN |
| ApJ Keywords: |
| GALAXIES: INDIVIDUAL NAME: MARKARIAN 273, GALAXIES: INTERACTIONS, GALAXIES: STARBURST |
| Abstract Copyright: |
| (c) 1995: The American Astronomical Society |
| Bibliographic Code: |
| 1995ApJ...451L..45Y |
Abstract
We present the first interferometric measurement of CO emission ( theta
~ 2") from the ultraluminous infrared galaxy Mrk 273. A total H2 mass of
3.6 x 1010 M&sun; is inferred from the CO observations, half of which
belongs to an extended component with deconvolved size 5.1 x 2.5 kpc. In
addition, an unresolved molecular gas complex is found to be coincident
with the optical nucleus. The inferred H2 mass, size (R ~ 380 pc), and
mean surface mass density ( Sigma _{{H}_{2}} >= 4 x 104 M&sun; pc-3) of
this complex, as well as the IR luminosity, are very similar to those of
Arp 220. The gas in the extended component shows a rotational velocity
gradient with the kinematic major axis aligned with the position angle
of the two nuclei seen in the near-infrared. The extended molecular gas
distribution and separation of the two nuclei suggest that Mrk 273 is a
young merger system. The CO emission appears confined to the edge-on
system, and the second merger progenitor may have been gas-poor or may
have had its gas transferred to the companion during the merger. The
comparison of the physical properties of Mrk 273 with two other
similarly gas-rich IR luminous systems, VV 114 and Arp 220, finds a
monotonic increase in average gas surface density and IR luminosity
efficiency (LIR/ M_{{H}_{2}} ) with decreasing projected separation of
the stellar nuclei. We find that now all four nearest ultraluminous
systems observed at high spatial resolution (Arp 220, Arp 299, Mrk 231,
and Mrk 273) are associated with central mass surface density in excess
of 104 M&sun; pc-2.
| Title: |
| Molecular Gas in Luminous Infrared Galaxies |
| Authors: |
| BRYANT, P. M.; SCOVILLE, N. Z. |
| Affiliation: |
| AA(Caltech) |
| Journal: |
| American Astronomical Society Meeting, 185, #68.03 |
| Publication Date: |
| 12/1994 |
| Origin: |
| AAS |
| Abstract Copyright: |
| (c) 1994: American Astronomical Society |
| Bibliographic Code: |
| 1994AAS...185.6803B |
Abstract
We have performed 2('') -resolution aperture synthesis observations of a
sample of luminous infrared galaxies in the CO(1--0) and HCN(1--0)
transitions with the Owens Valley Millimeter Array. Five of the six
galaxies are classified by their optical morphology as mergers, while
the other one is classified as a member of an interacting pair; all have
infrared luminosities equal to or greater than 10(11.5) L_{sun }. Our
observations show that the mergers have very large concentrations of
molecular gas in their nuclear regions, while the weaker interaction
shows a much more extensive gas distribution. As part of our analysis,
we have re-evaluated the behavior of the molecular gas mass to CO
luminosity ratio for a variety of different geometries in order to
better understand the uncertainties involved in the use of the standard
mass conversion factor.
The objects classified as mergers all have over 10(10) M_{sun } of gas
contained within a radius of 1.6 kpc, and one, Mrk 231, has this gas
within a radius of 0.5 kpc. The inferred molecular hydrogen column
densities of these objects range from 2 times 10(23) to 2 times 10(24)
cm(-2) . Since the nuclei can be clearly seen at 2 microns, the gas
must either be very clumpy or in a flattened, disk-like distribution.
Further evidence for a disk-like distribution for the molecular gas
comes from Mrk 231, whose derived gas mass is over six times the
dynamical mass estimated from its CO line width. We argue that it is
unlikely that the standard conversion factor is overestimating the gas
mass by such a large factor and thus that the gas is Mrk 231 resides in
a roughly face-on rotationally-supported disk.
In contrast to the merger objects, the galaxy NGC 7674, a member of an
interacting pair, shows a comparable amount of gas, but in a 11-kpc-long
bar-like feature. It is unclear whether this object represents a merger
event early in its evolution or a less violent interaction. In either
case, our observations of luminous infrared galaxies are consistent with
models of interacting galaxies, such as those of Barnes & Hernquist,
which show a rapid accumulation of gas in the central regions during a
merger event.
| Title: |
| Galaxies with extreme infrared and Fe II emission. 2: IRAS 07598+6508: A starburst/young broad absorption line QSO |
| Authors: |
| LIPARI, SEBASTIAN |
| Affiliation: |
| AASpace Telescope Science Inst., Baltimore, MD, US |
| Journal: |
| Astrophysical Journal, Part 1 (ISSN 0004-367X), vol. 436, no. 1, p. 102-111 |
| Publication Date: |
| 11/1994 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ABSORPTION SPECTRA, EMISSION SPECTRA, GALACTIC EVOLUTION, GALACTIC NUCLEI, INFRARED RADIATION, IRON, QUASARS, RED SHIFT, ASTRONOMICAL OBSERVATORIES, FLUX DENSITY, INFRARED PHOTOMETRY, LUMINOSITY, ULTRAVIOLET RADIATION, ULTRAVIOLET SPECTROSCOPY |
| Bibliographic Code: |
| 1994ApJ...436..102L |
Abstract
In this paper we investigate the nuclear properties of the extreme IR-Fe
II emitters IRAS 07598+6508 by means of UV-optical spectroscopy, and IR
photometry. The features shown in the UV region (by the IUE spectrum of
IRAS 07598+6508) are very similar to those obtained for high-redshift
low-ionization BAL QSOs (i.e., they show a strong blend of broad
absorption and emission lines with low and high state of ionization),
implying outflow velocities between 4000 and 18,000 km/s. The UV
continuum shows a clear deficit of UV photons at lambda less than 2000A;
and only weak Fe II(sub UV) emission was detected. On the other hand,
the optical emission spectrum of IRAS 07598+6508 shows the typical
features of extreme optical Fe II emitters, with Fe II(sub OPT)/Hbeta
approximately 8, Na I D/Halpha = 0.05, and (O III) lambda 5007/Hbeta
approximately 0.02 (very similar to the values obtained for Mrk 231).
Finally, IR-IRAS archival data were used in order to compare the IR
properties of this QSO in relation to extreme and strong IR-Fe II
emitters, and we found different locations in the IR color-color diagram
for these two groups of objects (i.e., the strong Fe II-IR emitters are
distributed mainly in the power-law area, while the extreme emitters are
located between the power-law and the blackbody region). In addition,
the IR and optical properties of some galaxies showing 'optical narrow
emission lines' and strong optical Fe II emission were studied. These
results and the nature of extreme and strong IR-Fe II emitters (showing
strong BAL systems and weak NLR) are discussed 'mainly ' in terms of a
dusty starburst/superwind scenario. We suggest that IRAS 07598+6508 is
probably an IR QSO where the nuclear starburst is in a more advanced
state than in Mrk 231, in particular, when the gas and dust (that were
obscuring the UV BLR and the UV photons) have been partially expelled by
the nuclear starburst/superwind. Also, we propose that the
extreme/strong Fe II emission (probably originated in the ejecta of Type
II supernovae (Terlevich et al. 1994a) and/or in the associated
superbubble) could be a sensible parameter in order to measure the
process of cleaning the nuclear dust and therefore is probably related
to the origin of the NLR mission and BAL system. Finally, an
evolutionary link between extreme and strong IR-Fe II emitters is
discussed.
| Title: |
| Spectropolarimetry of high-polarization Seyfert 1 galaxies: Geometry and kinematics of the scattering regions |
| Authors: |
| GOODRICH, R. W.; MILLER, J. S. |
| Affiliation: |
| AAUniv. of California, Santa Cruz, CA, US ABUniv. of California, Santa Cruz, CA, US |
| Journal: |
| Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 434, no. 1, p. 82-93 |
| Publication Date: |
| 10/1994 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| EMISSION SPECTRA, H ALPHA LINE, INTERSTELLAR MATTER, KINEMATICS, POLARIZED ELECTROMAGNETIC RADIATION, QUASARS, SEYFERT GALAXIES, ASTRONOMICAL MODELS, ASTRONOMICAL POLARIMETRY, ASTRONOMICAL SPECTROSCOPY, ELECTRON SCATTERING, FLUX DENSITY, POLARIMETERS, RED SHIFT |
| Bibliographic Code: |
| 1994ApJ...434...82G |
Abstract
We present moderate-resolution (10 A) spectropolarimetry of nine Seyfert
1 galaxies. Four of the objects are either essentially unpolarized (NGC
6212 and NGC 7469) or polarized by interstellar dust in our own Galaxy
(III Zw 2 and NGC 6814). The most striking result for the remainder is
that all of them show emission-line polarization and show evidence for
multiple sources of polarization. Some objects appear to be polarized by
dust reflection, others by electron scattering, and at least one by
both. These observations rule out simple, axisymmetric models of the
Seyfert nuclei and their immediate environment. The high polarization of
Mrk 231 results from light reflected by high-velocity dust clouds. The
new absorption system reported by Boroson et al. (1991) is visible in
our spectra, and we confirm the variability curve of this feature
reported by Kollatschny et al. (1992). The spectral polarization
structures of Mrk 376 and Mrk 704 are quite similar. In both Mrk 509 and
NGC 5548 the H-alpha lines appear broader in polarized flux than in
total flux, with P rising above the continuum P in the far wings. We
have proposed that Seyfert 1 galaxies and quasars are polarized by
scattering preferentially in the plane of a relatively thin disk.
However, the variety of effects seen in the polarization spectra of the
Seyfert 1's studied show that these simple models are not sufficient to
explain the details observed.
| Title: |
| CO absorption in luminous infrared galaxies |
| Authors: |
| RIDGWAY, SUSAN E.; WYNN-WILLIAMS, C. G.; BECKLIN, E. E. |
| Affiliation: |
| AAHawaii Univ., Honolulu, HI, US ABHawaii Univ., Honolulu, HI, US ACCalifornia Univ., Los Angeles, CA, US |
| Journal: |
| The Astrophysical Journal, vol. 428, no. 2, pt. 1, p. 609-616 |
| Publication Date: |
| 06/1994 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ABSORPTION SPECTRA, CARBON MONOXIDE, GALAXIES, HYDROGEN, INFRARED SOURCES (ASTRONOMY), INFRARED SPECTRA, MOLECULES, SILICATES, ARRAYS, GRATINGS, INFRARED PHOTOMETRY, SPECTROMETERS |
| Bibliographic Code: |
| 1994ApJ...428..609R |
Abstract
We have taken 2.2 micrometers window spectra of the nuclear regions of a
sample of 19 luminous infrared galaxies and used these to determine the
2.3 micrometer CO absorption feature. We have found a relationship
between the depth of the 2.3 micrometer absorption bands and the H-K
color of the galaxies. Galaxies with H-K colors in the range 0.4 to 0.8
tend to have deeper CO absorption than normal galaxies. Their
near-infrared emission is therefore probably dominated by late-type
supergiant or metal-rich giant stars that have been reddened by
interstellar dust. Galaxies with H-K colors redder than 0.9 tend to have
much weaker than normal CO absorption. Their near-infrared emission
therefore cannot be simply reddened starlight from late-type giant
stars, and they are likely to contain an additional source of
near-infrared radiation. The most likely possibilities are an active
galactic nucleus (AGN), or emission from very small transiently heated
dust grains. Of the five objects with reddest H-K colors and weakest CO
absorption, three (IRAS 05189-2524, UCG 5101 and Mrk 231) belong to the
ultraluminous class of IRAS galaxies and are known to have Seyfert
nuclei; two are off-nuclear components of the merging system Arp 299. We
have also detected for the first time strong emission lines of molecular
hydrogen in the infrared luminous galaxy NGC 4418, the galaxy with the
deepest known 10 micrometers silicate absorption feature.
| Title: |
| Molecular Gas in Luminous Infrared Galaxies |
| Authors: |
| BRYANT, P. M.; SCOVILLE, N. Z. |
| Affiliation: |
| AA(Caltech) |
| Journal: |
| American Astronomical Society Meeting, 184, #48.01 |
| Publication Date: |
| 05/1994 |
| Origin: |
| AAS |
| Abstract Copyright: |
| (c) 1994: American Astronomical Society |
| Bibliographic Code: |
| 1994AAS...184.4801B |
Abstract
We have performed 2('') -resolution aperture synthesis observations of a
sample of luminous infrared galaxies in the CO(1--0) and HCN(1--0)
transitions with the Owens Valley Millimeter Array. Five of the six
galaxies are classified by their optical morphology as mergers, while
the other one is classified as a member of an interacting pair; all have
infrared luminosities equal to or greater than 10(11.5) L_{sun }. Our
observations show that the mergers have very large concentrations of
molecular gas in their nuclear regions, while the weaker interaction
shows a much more extensive gas distribution.
The objects classified as mergers all have well over 10(10) M_{sun } of
gas contained within a radius of 1.6 kpc, and one, Mrk 231, has this gas
within a radius of 0.5 kpc. The inferred molecular hydrogen column
densities of these objects range from 2 times 10(23) to 2 times 10(24)
cm(-2) . If the gas were spread uniformly throughout the nuclear
regions, these numbers imply A_{V} ~ 100--1000 magnitudes. Since the
nuclei can be clearly seen at 2 microns, the gas must either be very
clumpy or in a flattened, disk-like distribution. Further evidence for a
disk-like distribution for the molecular gas comes from Mrk 231, whose
derived gas mass is nine times the dynamical mass estimated from its CO
line width. We argue that it is unlikely that the standard conversion
factor is overestimating the gas mass by such a large factor and thus
that the gas is Mrk 231 resides in a rotationally-supported disk whose
rotation axis is within 35 degrees of our line-of-sight.
In contrast to the merger objects, the galaxy NGC 7674, a member of an
interacting pair, shows a comparable amount of gas, but in a 11-kpc-long
bar-like feature. It is unclear whether this object represents a merger
event early in its evolution or a less violent interaction. In either
case, our observations of luminous infrared galaxies are consistent with
models of interacting galaxies, such as those of Barnes & Hernquist,
which show a rapid accumulation of gas in the central regions during a
merger event.
| Title: |
| Do the more powerful monsters live in the more actively star-forming host galaxies? |
| Authors: |
| YAMADA, TORU |
| Affiliation: |
| AAKyoto University, Kyoto, Japan |
| Journal: |
| Astrophysical Journal, Part 2 - Letters, vol. 423, no. 1, p. L27-L30 |
| Publication Date: |
| 03/1994 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTROPHYSICS, CARBON MONOXIDE, FAR INFRARED RADIATION, LUMINOSITY, QUASARS, RADIO EMISSION, SEYFERT GALAXIES, STAR FORMATION RATE, STARBURST GALAXIES, X RAYS, DATA CORRELATION, QUALITATIVE ANALYSIS, STELLAR MASS ACCRETION |
| Bibliographic Code: |
| 1994ApJ...423L..27Y |
Abstract
We have investigated the correlation between previously published X-ray
(0.5 to 4.5 keV) and carbon monoxide (CO) luminosity data of 13 Seyfert
1 galaxies and five quasars and found that there may be a significant
correlation between these quantities. The correlation between CO and
far-infrared luminosities of these objects is found to be similar to
those of the nearby spiral and starburst galaxies. These results may
indicate that the more powerful monsters live in the more actively
star-forming host galaxies. There are two distinct exceptions here,
however; Mrk 231, whose X-ray luminosity is smaller by two orders of
magnitude than the value expected from the correlation, and Mrk 376,
whose X-ray luminosity is too high by at least an order of magnitude
compared to the correlation. Confirmation of this potentially important
result with a larger and much more well-defined sample is urgently
needed.
| Title: |
| Guaranteed time observations support for Faint Object Spectrograph (FOS) on HST |
| Authors: |
| HARMS, RICHARD |
| Affiliation: |
| California Univ., La Jolla, CA. |
| Journal: |
| Technical Progress Report, 1 Nov. 1993 - 30 Apr. 1994 California Univ., La Jolla, CA. |
| Publication Date: |
| 00/1994 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTRONOMICAL PHOTOMETRY, ASTRONOMICAL POLARIMETRY, ASTRONOMICAL SPECTROSCOPY, GALACTIC HALOS, PECULIAR GALAXIES, SEYFERT GALAXIES, SPECTROGRAPHS, SPECTROPHOTOMETRY, HUBBLE SPACE TELESCOPE, LINE SPECTRA, STELLAR SPECTRA |
| Bibliographic Code: |
| 1994N94-37037.....H |
Abstract
The goals of the GTO effort are for investigations defined in previous
years by the IDT to be carried out as HST observations and for the
results to be communicated to the scientific community and to the
public. The search for possible black holes in the nuclei of both normal
and active nucleus galaxies has had to be delayed to the post-servicing
era. FOS spectropolarimetric observations of the nuclear region of the
peculiar Seyfert galaxy Mrk 231 reveal that the continuum polarization
peaks at 18% in the near UV and then declines rapidly toward shorter
wavelengths. The papers on the absorption line analysis for our galactic
halo address the spatial distribution of high and intermediate level
ions in the halo and illustrate the patchy and heterogeneous nature of
the halo. The papers on the scattering characteristics of the HST/FOS
have provided us with data that shows that the HST mirror surfaces are
quite smooth, even at the UV wavelengths. WF-PC and FOC images of the
halo PN K648 have been fully analyzed.
| Title: |
| Compact starbursts in ultraluminous infrared galaxies |
| Authors: |
| CONDON, J. J.; HUANG, Z.-P.; YIN, Q. F.; THUAN, T. X. |
| Affiliation: |
| AC(National Radio Astronomy Observatory, Charlottesville, VA) AD(Virginia, University, Charlottesville) |
| Journal: |
| Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 378, Sept. 1, 1991, p. 65-76. |
| Publication Date: |
| 09/1991 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| INFRARED SOURCES (ASTRONOMY), LUMINOSITY, RADIO SOURCES (ASTRONOMY), STARBURST GALAXIES, BRIGHTNESS TEMPERATURE, FAR INFRARED RADIATION, INFRARED ASTRONOMY SATELLITE, RADIO SPECTRA |
| Bibliographic Code: |
| 1991ApJ...378...65C |
Abstract
The 40 ultraluminous galaxies in the IRAS Bright Galaxy Sample of
sources stronger than S = 5.24 Jy at lambda = 60 microns were mapped
with approximately 0.25 arcsec resolution at 8.44 GHz. Twenty-five
contain diffuse radio sources obeying the FIR-radio correlation; these
are almost certainly starburst galaxies. Fourteen other galaxies have
nearly blackbody FIR spectra with color temperatures between 60 and 80 K
so their (unmeasured) FIR angular sizes must exceed approximately 0.25
arcsec, yet they contain compact (but usually resolved) radio sources
smaller than this limit. The unique radio and FIR properties of these
galaxies can be modeled by ultraluminous nuclear starbursts so dense
that they 67 are optically thick to free-free absorption at about 1.49
GHz and dust absorption at about 25 microns. Only one galaxy (UGC 08058
= Mrk 231) is a dominated by a variable radio source too compact to be
an ultraluminous starburst; it must be powered by a 'monster'.
| Title: |
| CO excitation and H2 masses of infrared-luminous galaxies |
| Authors: |
| RADFORD, SIMON J. E.; DOWNES, D.; SOLOMON, P. M. |
| Affiliation: |
| AB(Institut de Radioastronomie Millimetrique, Saint-Martin-d'Heres, France) AC(Grenoble, Observatoire, France; Max-Planck-Institut fuer Radioastronomie, Bonn, Federal Republic of Germany; New York, State University, Stony Brook) |
| Journal: |
| Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X), vol. 368, Feb. 10, 1991, p. L15-L18. |
| Publication Date: |
| 02/1991 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| CARBON MONOXIDE, GALACTIC RADIATION, GAS DENSITY, HYDROGEN, INFRARED SOURCES (ASTRONOMY), INTERSTELLAR GAS, MOLECULAR CLOUDS, MOLECULAR EXCITATION, BRIGHTNESS TEMPERATURE, DENSITY MEASUREMENT, MASS TO LIGHT RATIOS, MILKY WAY GALAXY, QUASARS |
| Bibliographic Code: |
| 1991ApJ...368L..15R |
Abstract
The CO(2-1) and CO(1-0) emission from four infrared-luminous galaxies,
Arp 193, Arp 220, Mrk 231, and VII Zw 31, was mapped with the IRAM 30 m
telescope. These maps show the molecular gas is concentrated in the
central regions. The CO(2-1)/CO(1-0) brightness temperature ratio for
these galaxies is low, 0.6-0.75, indicating the CO is subthermally
excited in regions of moderate H2 density, roughly 400/cu cm. The
intrinsic CO(1-0) brightness temperatures are inferred to be between 6
and 13 K, even if the gas kinetic temperatures are much higher. For
these galaxies, the H2 mass-to-CO luminosity ratio is similar to that
measured for giant molecular clouds in the Milky Way molecular ring.
| Title: |
| CO excitation in four IR luminous galaxies |
| Authors: |
| RADFORD, SIMON J. E.; SOLOMON, P. M.; DOWNES, DENNIS |
| Affiliation: |
| AB(State Univ. of New York, Stony Brook.) |
| Journal: |
| In NASA, Ames Research Center, The Interstellar Medium in External Galaxies: Summaries of Contributed Papers p 378-380 (SEE N91-14100 05-90) |
| Publication Date: |
| 07/1990 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ACTIVE GALAXIES, CARBON MONOXIDE, EXCITATION, FAR INFRARED RADIATION, GALACTIC RADIATION, INFRARED RADIATION, LUMINOSITY, MOLECULAR CLOUDS, MOLECULAR GASES, SPIRAL GALAXIES, STAR FORMATION, CALIBRATING, HYDROGEN, MILKY WAY GALAXY, TELESCOPES |
| Bibliographic Code: |
| 1990imeg.conf..378R |
Abstract
The correlation between the CO and far infrared luminosities of spiral
galaxies is well established. The luminosity ration, L sub FIR/L sub CO
in IR luminous active galaxies is, however, systematically five to ten
times higher than in ordinary spirals and molecular clouds in our
Galaxy. Furthermore, the masses of molecular hydrogen in luminous
galaxies are large, M (H2) approx. equals 10(exp 10) solar magnitude,
which indicates the observed luminosity ratios are due to an excess of
infrared output, rather than a deficiency of molecular gas. These large
amounts of molecular gas may fuel luminous galaxies through either star
formation or nuclear activity. This interpretation rests on applying the
M (H2)/L sub CO ratio calibrated in our Galaxy to galaxies with
strikingly different luminosity ratios. But are the physical conditions
of the molecular gas different in galaxies with different luminosity
ratios. And, if so, does the proportionality between CO and H2 also vary
among galaxies. To investigate these questions researchers observed CO
(2 to 1) and (1 to 0) emission from four luminous galaxies with the
Institute for Radio Astronomy in the Millimeter range (IRAM) 30 m
telescope. Researchers conclude that most of the CO emission from these
Arp 193, Arp 220, and Mrk 231 arises in regions with moderate ambient
densities similar to the clouds in the Milky Way molecular ring. The
emission is neither from dense hot cloud cores nor from the cold low
density gas characteristic of the envelopes of dark clouds.
| Title: |
| Temperature distribution of dust in luminous IRAS galaxies |
| Authors: |
| CARICO, DAVID P. |
| Affiliation: |
| California Inst. of Tech., Pasadena. |
| Journal: |
| In NASA, Ames Research Center, Interstellar Dust: Contributed Papers p 325-329 (SEE N91-14897 06-88) |
| Publication Date: |
| 12/1989 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| COSMIC DUST, GALAXIES, INFRARED ASTRONOMY SATELLITE, INFRARED RADIATION, LUMINOSITY, TEMPERATURE DISTRIBUTION, ASTRONOMICAL OBSERVATORIES, CONTINUUMS, SUBMILLIMETER WAVES, TELESCOPES |
| Bibliographic Code: |
| 1989idcp.rept..325C |
Abstract
Work is currently in progress to obtain temperature distributions of
dust in the most infrared-luminous galaxies. The results presented are
of a preliminary nature, representing a zeroth-order approximation. The
objects which have been analyzed so far are all galaxies from the
Infrared Astronomy Satellite (IRAS) Bright Galaxy Sample with infrared
luminosities L sub IR greater than or equal to 10(exp 11) solar
luminosity. They are: Arp 220, Mrk 231, Mrk 273, NGC 1614, NGC 3690, NGC
6285/6, and Zw 049.057. The analysis utilized 3.7 micron data from the
Palomar 5 m Hale telescope, IRAS data at 12, 25, 60, and 100 microns,
and 1 mm continuum data from the CalTech Submillimeter Observatory on
Mauna Kea.
| Title: |
| Aperture synthesis of CO emission in extremely luminous infrared galaxies |
| Authors: |
| SCOVILLE, N. Z.; SANDERS, D. B.; SARGENT, A. I.; SOIFER, B. T.; TINNEY, C. G. |
| Affiliation: |
| AE(California Institute of Technology, Pasadena) |
| Journal: |
| Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X), vol. 345, Oct. 1, 1989, p. L25-L28. |
| Publication Date: |
| 10/1989 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| CARBON MONOXIDE, EMISSION SPECTRA, GALACTIC RADIATION, INFRARED SOURCES (ASTRONOMY), MARKARIAN GALAXIES, ACTIVE GALACTIC NUCLEI, INFRARED ASTRONOMY SATELLITE, LUMINOSITY, MOLECULAR GASES, STAR CLUSTERS, SYNTHETIC ARRAYS |
| Bibliographic Code: |
| 1989ApJ...345L..25S |
Abstract
High-resolution aperture synthesis mapping of the CO (J = 1-0) emission
has been carried out for the extremely luminous IRAS galaxies, VV 114,
NGC 1614, VII Zw 31, and Mrk 231. For all of the galaxies except for VV
114, the observations show the existence of compact emission sources
centered on the optical/IR nuclei. In VV 114, the observations reveal
two concentrations of emission extending over an area of about 4 kpc.
The mean molecular gas surface densities averaged over the compact
regions of the galaxies reach 3000 solar masses/sq pc. It is suggested
that the concentration of large masses of molecular gas in galactic
nuclei initiates energetic activity in these galaxies via a nuclear
starburst, possibly resulting in the formation of an active galactic
nucleus.
| Title: |
| Infrared polarimetry of galaxies. I - Infrared luminous galaxies |
| Authors: |
| JONES, TERRY JAY; KLEBE, DIMITRI |
| Affiliation: |
| AB(Minnesota, University, Minneapolis) |
| Journal: |
| Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 341, June 15, 1989, p. 707-717. |
| Publication Date: |
| 06/1989 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTRONOMICAL PHOTOMETRY, GALAXIES, INFRARED SOURCES (ASTRONOMY), LUMINOSITY, POLARIMETRY, GALACTIC STRUCTURE, INFRARED ASTRONOMY, INTERSTELLAR MATTER |
| Bibliographic Code: |
| 1989ApJ...341..707J |
Abstract
Polarimetric observations at 1.2, 1.65, and 2.2 microns are presented
for six infrared luminous galaxies. The polarimetric properties of these
galaxies span a wide range of behavior from a simple screen of aligned
dust grains in Arp 220 to powerful nonthermal emission in IRAS
05189-2524. Mrk 231 shows a strong rise in polarization to the blue
which can be modeled as scattering from a moderately obscured source.
UGC 5101 show a very peculiar and dramatic rise in polarization from 1
to 2.2 microns, suggesting dilution of a steep nonthermal source at the
shorter wavelengths. NGC 6240 is only weakly polarized and Mrk 273 is
unpolarized at the 0.4 percent level in the near infrared. The galaxies
with the faintest absolute K magnitudes, show weak polarization,
suggesting the near-infrared light from their nuclear region is not
associated with the dusty and very luminous source of longer wavelength
emission unless the magnetic field within this dusty region is extremely
disordered. The data suggests that very luminous galaxies with an energy
distribution dominated by heated dust are likely to show weak simple
interstellar polarization whereas galaxies with more quasar-like
continua are likely to show unusual and more complex polarimetric
behavior.
| Title: |
| Detection of CO(1 to 0) emission from infrared quasars and luminous Seyfert galaxies |
| Authors: |
| SANDERS, D. B.; SCOVILLE, N. Z.; ZENSUS, A.; SOIFER, B. T.; WILSON, T. L.; ZYLKA, R.; STEPPE, H. |
| Affiliation: |
| AD(California Institute of Technology, Pasadena) AE(Max-Planck-Institut fuer Radioastronomie, Bonn, Federal Republic of Germany) |
| Journal: |
| Astronomy and Astrophysics (ISSN 0004-6361), vol. 213, no. 1-2, April 1989, p. L5-L8. Research supported by NASA IRAS Extended Mission Program. |
| Publication Date: |
| 04/1989 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| CARBON MONOXIDE, INFRARED SOURCES (ASTRONOMY), QUASARS, SEYFERT GALAXIES, ACTIVE GALACTIC NUCLEI, LIGHT SPEED, LUMINOSITY, MARKARIAN GALAXIES, MOLECULAR CLOUDS, RED SHIFT |
| Bibliographic Code: |
| 1989A&A...213L...5S |
Abstract
CO(1 to 0) emission has been detected from the infrared quasar IRAS
07598+6508 and the luminous Seyfert galaxies IRAS 08572+3915 and
Markarian 463 with the IRAM 30-m telescope. These objects were selected
from a complete list of warm ultraluminous IRAS sources. The maximum
redshift observed was 0.149 (cz = 44.621 km/s , IRAS 07598+6508).
Assuming the same empirical relationship between CO brightness and H2
surface mass density as has been found for giant molecular clouds in the
Milky Way, the mass of H2 gas in these objects is in the range 0.7 - 6 x
10 to the 10th solar masses, more than 2 - 20 times the H2 content of
the Galaxy. The infrared and molecular gas properties of these galaxies
are similar to other 'warm' ultraluminous infrared galaxies such as Mrk
231, and the UV-excess quasar Mrk 1014. It is suggested that objects
such as these represent an important link in the evolution of
ultraluminous infrared galaxies into UV-excess quasars.
| Title: |
| Detection of abundant molecular gas in the UV-excess quasar Markarian 1014 |
| Authors: |
| SANDERS, D. B.; SCOVILLE, N. Z.; SOIFER, B. T. |
| Affiliation: |
| AC(California Institute of Technology, Pasadena) |
| Journal: |
| Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X), vol. 335, Dec. 1, 1988, p. L1-L4. |
| Publication Date: |
| 12/1988 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| INTERACTING GALAXIES, INTERSTELLAR MATTER, MARKARIAN GALAXIES, MOLECULAR SPECTRA, QUASARS, ULTRAVIOLET SPECTRA, ACTIVE GALACTIC NUCLEI, ASTRONOMICAL MODELS, CARBON MONOXIDE, STARBURST GALAXIES |
| Bibliographic Code: |
| 1988ApJ...335L...1S |
Abstract
CO(1-0) emission has been detected from the UV-excess quasar Mrk 1014 (
= PG 0157+001 = IRAS 01572+0009) at z = 0.163. Assuming the same
empirical relationship between CO brightness and H2 surface mass density
as has been found for giant molecular clouds in the Milky Way, the mass
of H2 gas is about 4 x 10 to the 10th solar masses more than 10 times
the H2 content of the Galaxy. The infrared and molecular gas properties
of Mrk 1014 are similar to other 'warm', ultraluminous infrared galaxies
such as Mrk 231, and IRAS 15206+3342 (z = 0.125) from which CO(1-0)
emission is also reported. The trigger for the intense infrared activity
in both Mrk 1014 and IRAS 15206+3342 appears to be a recent galaxy
merger. It is suggested that objects such as these represent an
important link in the evolution of ultraluminous infrared galaxies into
UV-excess quasars.
| Title: |
| Calcium infrared triplet emission in active galactic nuclei |
| Authors: |
| PERSSON, S. E. |
| Affiliation: |
| AA(Mount Wilson and Las Campanas Observatories, Pasadena, CA) |
| Journal: |
| Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 330, July 15, 1988, p. 751-765. NSF-supported research. |
| Publication Date: |
| 07/1988 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ACTIVE GALACTIC NUCLEI, INFRARED SOURCES (ASTRONOMY), INFRARED SPECTRA, CALCIUM, IRON, LINE SPECTRA, OXYGEN, QUASARS, SEYFERT GALAXIES, SPECTRAL LINE WIDTH |
| Bibliographic Code: |
| 1988ApJ...330..751P |
Abstract
Emission in the Ca II infrared triplet lines has been detected in at
least nine, and probably 14, active galactic nuclei, out of a total of
40 surveyed. The Ca II line strengths are roughly correlated with the
strength of optical Fe II emission and appear over a wide range of
luminosity, BLR linewidth, and forbidden O III/H-beta ratio. Calcium
emission is thus a general property of AGN that have extremely dense and
neutral gas near the active nucleus. The Ca II linewidth is correlated
with that of the 8446 A O I line, indicating that the Ca(+) zone is
intimately associated with the broad-line region. An exception is Mrk
231, in which the Ca II linewidths are significantly narrower than that
of the O I line; kinematically distinct region, perhaps in the form of a
disk, is indicated. The level of ionization in the zone that gives rise
to the optically thick calcium lines is very low, with neutral carbon
providing the shielding for the Ca(+) ions from the incident ultraviolet
continuum. If these ultradense zones are heated by a nonradiative
mechanism, as advocated by Collin-Souffrin, Joly, and others, and if
such heating occurs in the accretion disk, then the kinematical
information conveyed by the Ca II lines indicates that in general the
BLR lies close to the disk plane.
| Title: |
| Detection of abundant molecular gas in the UV-excess quasar Mrk 1014 |
| Authors: |
| SANDERS, D. B.; SCOVILLE, N. Z.; SOIFER, B. T. |
| Affiliation: |
| California Inst. of Tech., Pasadena. |
| Journal: |
| Detection of abundant molecular gas in the UV-excess quasar Mrk 1014 |
| Publication Date: |
| 00/1988 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ABUNDANCE, HYDROGEN CLOUDS, QUASARS, ULTRAVIOLET ASTRONOMY, CARBON DIOXIDE, GALACTIC EVOLUTION, INFRARED RADIATION, MILKY WAY GALAXY, MOLECULAR CLOUDS |
| Bibliographic Code: |
| 1988N88-28842.....S |
Abstract
Carbon dioxide (1 yields 0) emission has been detected from the
UV-excess quasar Mrk 1014 (=PG 0157+001=IRAS 01572+0009) at z=0.163.
Assuming the same empirical relationship between CO brightness and H2
surface mass density as has been found for giant molecular clouds in the
Milky Way, the mass of H2 gas is approximately 4 x 10 to the 10th solar
masses, i.e., more than ten times the H2 content of our Galaxy. The
infrared and molecular gas properties of Mrk 1014 are similar to other
warm, ultraluminous infrared galaxies such as Mrk 231, and IRAS
15206+3342 (z=0.125) from which CO(1 yields 0) emission is also
reported. The trigger for the intense infrared activity in both Mrk 1014
and IRAS 15206+3342 appears to be a recent galaxy merger. It is
suggested that objects such as these represent an important link in the
evolution of ultraluminous infrared galaxies into UV-excess quasars.
| Title: |
| A systematic search for OH megamasers |
| Authors: |
| STAVELEY-SMITH, L.; COHEN, R. J.; CHAPMAN, J. M.; POINTON, L.; UNGER, S. W. |
| Affiliation: |
| AE(Manchester, Victoria University, Jodrell Bank, England) |
| Journal: |
| Royal Astronomical Society, Monthly Notices (ISSN 0035-8711), vol. 226, June 1, 1987, p. 689-701. |
| Publication Date: |
| 06/1987 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| EXTRAGALACTIC RADIO SOURCES, HYDROXYL EMISSION, INFRARED SOURCES (ASTRONOMY), INTERSTELLAR MASERS, LINE SPECTRA, ACOUSTO-OPTICS, LUMINOSITY, MOLECULAR SPECTRA, RADIANT FLUX DENSITY, SEYFERT GALAXIES |
| Bibliographic Code: |
| 1987MNRAS.226..689S |
Abstract
A sensitive search for powerful OH masers in external galaxies has been
carried out with the Jodrell Bank Mk1A radio telescope and a new
acoustooptical spectrometer. Candidate sources were selected from the
IRAS Point Source Catalog on the basis of their IR colors and were
searched for OH mainline emission at 18-cm wavelength, with a velocity
coverage of 17,000 km/s and a resolution of 40 km/s. A typical detection
level of 14 mJy was achieved. One new source, III Zw 35, was discovered.
This source has an exceptionally large ratio of OH to IR flux density.
The search has also revealed high-velocity wings in the OH emission from
the two Seyfert galaxies, Mrk 231 and 273. The velocity widths are too
high to be accounted for by galactic rotation, which suggests that the
molecular gas may be closely associated with the Seyfert nuclei.
| Title: |
| Extragalactic OH megamasers in strong IRAS sources |
| Authors: |
| BOTTINELLI, L.; DENNEFELD, H.; GOUGUENHEIM, L.; MARTIN, J. M.; PATUREL, G.; LESQUEREN, A. M. |
| Affiliation: |
| AE(Observatoire de Lyon, France ) |
| Journal: |
| In NASA, Washington Star Formation in Galaxies p 597-600 (SEE N87-24266 17-89) |
| Publication Date: |
| 05/1987 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| EXTRAGALACTIC RADIO SOURCES, FAR INFRARED RADIATION, HYDROXYL EMISSION, INTERSTELLAR MASERS, LINE SPECTRA, STELLAR SPECTRA, FLUX DENSITY, INFRARED ASTRONOMY SATELLITE, STELLAR LUMINOSITY |
| Bibliographic Code: |
| 1987sfig.conf..597B |
Abstract
From the OH and HI survey of the strongest far infrared IRAS sources, 3
new powerful OH megamasers were discovered in Arp 143, IRAS 1510+0724
and in the uncatalogued IRAS source, IRAS 17208-0014. The HI line, the
OH 1667 and 1665 MHz main lines and the 21 cm continuum observations
were made with Nancy radio telescope. The optical spectra and images
were obtained at the European Southern Observatory. The spectra are
displayed in figures together with the main IR and OH properties of the
8 megamasers detected up to now, including IC 4553, NGC 3690 and Mrk
231, Mrk 273 and III ZW35.
Abstract
IAUC 4379 available courtesy of the Central Bureau for Astronomical Telegrams.
IAUC 4379 available courtesy of the Central Bureau for Astronomical Telegrams.
| Title: |
| IRAS 1211+03 |
| Authors: |
| KAZES, I.; MIRABEL, I. F.; SANDERS, D. B. |
| Journal: |
| IAU Circ., 4362, 2 (1987). Edited by Green, D. W. E. |
| Publication Date: |
| 04/1987 |
| Origin: |
| CBAT |
| Objects: |
| IRAS 1211+03 |
| Bibliographic Code: |
| 1987IAUC.4362....2K |
Abstract
IAUC 4362 available courtesy of the Central Bureau for Astronomical Telegrams.
| Title: |
| 5 cm OH absorption toward the megamaser galaxy IC 4553 |
| Authors: |
| HENKEL, C.; GUESTEN, R.; BATRLA, W. |
| Affiliation: |
| AB(Max-Planck-Institut fuer Radioastronomie, Bonn, West Germany) AC(Illinois, University, Urbana) |
| Journal: |
| Astronomy and Astrophysics (ISSN 0004-6361), vol. 168, no. 1-2, Nov. 1986, p. L13-L15. |
| Publication Date: |
| 11/1986 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ABSORPTION SPECTRA, CENTIMETER WAVES, GALACTIC STRUCTURE, HYDROXYL EMISSION, INTERSTELLAR MASERS, RADIO SPECTRA, ENERGY LEVELS, FAR INFRARED RADIATION, PHOTONS |
| Bibliographic Code: |
| 1986A&A...168L..13H |
Abstract
Absorption in the 2Pi3/2 J = 5/2 main line of OH at 6035 is reported
from the OH megamaser galaxy IC 4553, based on observations obtained in
June 1986 with the 42.6-m NRAO telescope at Green Bank. Data set an
upper limit for Mrk 231, and an OH rotational temperature between the
2Pi3/2 J = 5/2 and 3/2 ground levels for IC 4553 of about 45 K is
derived which is close to the dust temperature, 61 K, of the parent
galaxy. Possible pumping mechanisms for the inversion of the ground
state doublet are considered, and it is suggested that OH excitation
involves pumping by 79 and 119 micron FIR photons and 5 and 6 cm
centimeter wave photons.
| Title: |
| New ultra-luminous galaxies |
| Authors: |
| FAIRCLOUGH, J. H. |
| Affiliation: |
| AA(SERC, Rutherford Appleton Laboratory, Didcot, England) |
| Journal: |
| Royal Astronomical Society, Monthly Notices (ISSN 0035-8711), vol. 219, March 1, 1986, p. 1P-4P. |
| Publication Date: |
| 03/1986 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| GALACTIC RADIATION, INFRARED ASTRONOMY, LUMINOSITY, ASTRONOMICAL PHOTOMETRY, INFRARED ASTRONOMY SATELLITE |
| Bibliographic Code: |
| 1986MNRAS.219P...1F |
Abstract
The IRAS survey has revealed seven more galaxies with infrared
luminosities of at least 10 to the 12th solar luminosities. One galaxy,
MRK 1014, equals MRK 231 in infrared luminosity. All of the galaxies are
in optical, ultraviolet and radio catalogs, and all but one show signs
of activity or structural peculiarity.
| Title: |
| The fourth OH megamaser - Markarian 273 |
| Authors: |
| BAAN, W. A.; SCHMELZ, J. T.; HASCHICK, A. D. |
| Affiliation: |
| AB(Arecibo Observatory, PR) AC(Haystack Observatory, Westford, MA) |
| Journal: |
| Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X), vol. 298, Nov. 15, 1985, p. L51-L54. |
| Publication Date: |
| 11/1985 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| HYDROXYL EMISSION, INFRARED RADIATION, INTERSTELLAR MASERS, SEYFERT GALAXIES, EMISSION SPECTRA, LINE SPECTRA, RADIAL VELOCITY |
| Bibliographic Code: |
| 1985ApJ...298L..51B |
Abstract
A fourth OH megamaser has been found in the luminous IR galaxy Mrk 273
(= U08696). The characteristics of this masing galaxy are similar to
those of the other powerful extragalactic masers in NGC 3690, IC 4553,
and Mrk 231. The 1667 MHz line luminosity of Mrk 273 is 335 L solar
luminosities. The IR photon-to-OH photon conversion efficiency is
calculated for all OH megamasers and is found to be close to 1 percent.
| Title: |
| Detection of distant extragalactic OH in absorption |
| Authors: |
| KAZES, I.; DICKEY, J. M. |
| Affiliation: |
| AA(Paris, Observatoire, Meudon, France) AB(Paris, Observatoire, Meudon, France; Minnesota, University, Minneapolis) |
| Journal: |
| Astronomy and Astrophysics (ISSN 0004-6361), vol. 152, no. 1, Nov. 1985, p. L9-L11. |
| Publication Date: |
| 11/1985 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| EXTRAGALACTIC RADIO SOURCES, HYDROXYL RADICALS, INTERSTELLAR MASERS, MOLECULAR CLOUDS, RADIO ASTRONOMY, ABSORPTION SPECTRA, LUMINOSITY |
| Bibliographic Code: |
| 1985A&A...152L...9K |
Abstract
OH absorption features were observed at greater than 200 Mpc distance
from the galaxy B2 1506 + 34. The data were collected with the 200 x 40
m radio telescope at the Paris Observatory in 1984. Linear polarizations
were observed at 1667 and 1665 MHz, with the data being fed through a
1024 channel autocorrelator. The spectral data covered 8.35 MHz, i.e.,
about 1500 km/sec. OH absorption data are presented for the objects NGC
2623, Mrk 231, NGC 5506 and B2 1506 + 34. The 1667/1665 flux ratio
varied from 0.9-2.1 indicating the presence of a molecular gas with a 10
K temperature and column densities one to two orders of magnitude larger
than those in our Galaxy.
| Title: |
| Powerful extragalactic masers |
| Authors: |
| BAAN, W. A. |
| Affiliation: |
| AA(Arecibo Observatory, Arecibo, PR) |
| Journal: |
| Nature (ISSN 0028-0836), vol. 315, May 2, 1985, p. 26-31. |
| Publication Date: |
| 05/1985 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| BACKGROUND RADIATION, EMISSION SPECTRA, EXTRAGALACTIC RADIO SOURCES, HYDROXYL EMISSION, INTERSTELLAR MASERS, WATER MASERS, BRIGHTNESS TEMPERATURE, FLUX (RATE), HYPERFINE STRUCTURE, LUMINOSITY, MOLECULAR CLOUDS, OPTICAL PUMPING, RADIAL VELOCITY, RED SHIFT |
| Bibliographic Code: |
| 1985Natur.315...26B |
Abstract
Two strong extragalactic OH masers have been detected in the galaxies
NGC3690 and Mrk 231 which are in the same class as the megamaser source
IC4553 (Arp 220). The amplification model for the background continuum
proposed for IC4553 can account for most of the powerful OH maser lines
and for part of the H2O emission. Most masing galaxies have sufficient
infrared flux to pump the masing regions, except that the H2O pumping
must occur at a much higher conversion efficiency than the OH pumping.
| Title: |
| Ca II emission in I Zwicky 1 |
| Authors: |
| PERSSON, S. E.; MCGREGOR, P. J. |
| Affiliation: |
| AB(Mount Wilson and Las Campanas Observatories, Pasadena, CA) |
| Journal: |
| Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 290, March 1, 1985, p. 125-129. NSF-supported research. |
| Publication Date: |
| 03/1985 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ABUNDANCE, ASTRONOMICAL PHOTOMETRY, EMISSION SPECTRA, GALACTIC NUCLEI, MOLECULAR CLOUDS, SEYFERT GALAXIES, B STARS, CALCIUM, H ALPHA LINE, INFRARED SPECTRA, LYMAN SPECTRA, PHOTOIONIZATION |
| Bibliographic Code: |
| 1985ApJ...290..125P |
Abstract
Spectrophotometric data betwen 6000 and 10000 A of the nucleus of the
Seyfert 1 galaxy I Zwicky 1 are presented. The brightest emission lines
in this spectral region are the 8446 A line of O I, the 8498, 8542, and
8662 A lines of Ca II (the infrared triplet), and a strong blend of
low-excitation lines near H I Pa9. Through a contrast with other
galaxies, the I Zw 1 and Mrk 231 are inferred to exhibit physical
conditions in the Ca II emission zones within the broad-line region,
that are similar to low-ionization zones in such galactic emission-line
objects as the Be stars and the young stellar objects that drive bipolar
outflows in molecular clouds. The young stellar object GL 490 is shown
to be a definitive example.
| Title: |
| THE INFLUENCE OF GALAXY INTERACTIONS ON NUCLEAR ACTIVITY |
| Authors: |
| CUTRI, ROC MICHAEL |
| Affiliation: |
| THE UNIVERSITY OF ARIZONA. |
| Journal: |
| Thesis (PH.D.)--THE UNIVERSITY OF ARIZONA, 1985.Source: Dissertation Abstracts International, Volume: 46-09, Section: B, page: 3090. |
| Publication Date: |
| 00/1985 |
| Category: |
| Physics: Astronomy and Astrophysics |
| Origin: |
| UMI |
| Keywords: |
| INFRARED, PHOTOMETRY |
| Abstract Copyright: |
| (c) 1985: UMI Company |
| Bibliographic Code: |
| 1985PhDT........57C |
Abstract
This dissertation examines empirically the effects of gravitational
interactions between galaxies on their respective nuclei with the
primary motivation of investigating the possible connection between such
interactions and the presence of vigorous nuclear activity. To carry out
this work, ground based near and mid-infrared observations, along with
the mid- and far infrared data of IRAS of a statistically complete
sample of interacting galaxies drawn from the Catalog of Isolated Pairs
of Galaxies in the Northern Hemisphere (Karachentsev 1972) were
utilized. Also performed were detailed probes of four known active,
interacting and possible interacting systems, which made use of infrared
multiaperture photometry and spectrophotometry. Comparison of the
nuclear infrared properties of the interacting galaxies with samples of
non-interacting galaxies shows that abnormal activity, characterized by
excess 10 (mu)m emission or extremely red or blue near infrared colors,
is much more common in the interacting systems. In particular, a
population of nuclei with extremely luminous 10 (mu)m emission appears
to be unique to the interacting sample. The in-depth studies of
individual active systems have revealed extended 3.3 (mu)m emission
around the nucleus of NGC 7469, implying the presence of an extended
heating source. The most plausible such source are the hot stars
associated with star forming regions surrounding the Seyfert nucleus.
The extraordinary Seyfert galaxy Mrk 231 may also be the site for
powerful star formation, as evidenced by the extreme luminosity of the
extended stellar system containing the Seyfert nucleus. This star
formation may have resulted from the assimilation of a small satellite
galaxy with a giant elliptical, or a collision between smaller systems.
Tools similar to those used to probe NGC 7469 and Mrk 231 were used to
investigate the interacting systems of NGC 6240 and Arp 220. These two
objects are found to be the sites of star formation on an unprecedented
scale, possibly involving up to 10('10) M(,o) of material. The evidence
suggesting the presence of these "super starbursts" includes an
exceedingly luminous extended stellar component seen at 2 (mu)m, a large
population of red supergiants implied by deep stellar CO absorption,
strong 3.3 (mu)m emission and 9.7 (mu)m silicate absorption, and an
extended luminosity source indicated by the extent of the 10 (mu)m
emission. Both of these galaxies exhibit prominent lines of shocked
molecular hydrogen which may arise in the collision of their
interstellar clouds in an ongoing interaction.
| Title: |
| OH Megamasers |
| Authors: |
| BAAN, W. A.; HASCHICK, A. D.; SCHMELZ, J. T. |
| Journal: |
| IAU Circ., 3993, 2 (1984). Edited by Marsden, B. G. |
| Publication Date: |
| 09/1984 |
| Origin: |
| CBAT |
| Objects: |
| OH Megamasers |
| Bibliographic Code: |
| 1984IAUC.3993....2B |
Abstract
IAUC 3993 available courtesy of the Central Bureau for Astronomical Telegrams.
IAUC 3993 available courtesy of the Central Bureau for Astronomical Telegrams.
| Title: |
| The dusty, luminous broad-line radio galaxy 3C 109 |
| Authors: |
| RUDY, R. J.; SCHMIDT, G. D.; STOCKMAN, H. S.; TOKUNAGA, A. T. |
| Affiliation: |
| AC(Steward Observatory, Tucson, AZ) AD(Hawaii, University, Honolulu, HI) |
| Journal: |
| Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 278, March 15, 1984, p. 530-535. |
| Publication Date: |
| 03/1984 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTRONOMICAL PHOTOMETRY, COSMIC DUST, INFRARED ASTRONOMY, POLARIMETRY, RADIO GALAXIES, GALACTIC NUCLEI, INTERSTELLAR EXTINCTION, QUASARS, SEYFERT GALAXIES |
| Bibliographic Code: |
| 1984ApJ...278..530R |
Abstract
In the present optical polarimetry and IR photometry for the broad line
radio galaxy 3C 109, the absence of variability, in conjunction with a
polarization in H-alpha that is identical to that of the adjacent
continuum, suggests that the strong polarization of this galaxy is due
to extinction by aligned dust grains. This is the process which gives
rise to interstellar polarization within the Galaxy. The energy output
of 3C 109, from the optical to 20 microns, exceeds by a factor of 2-4
that of the Seyfert 1 galaxy Markarian 231. These observations, together
with recent polarimetry of other broad line radio galaxies, indicate
that their broad line regions are more heavily reddened than those of
either the Seyfert 1 galaxies or quasars. Evidence for a gradual
decrease in dust content with increasing source luminosity is
discussed.
| Title: |
| An accretion disk origin for the ultraviolet continuum in Seyfert 1 galaxies and quasars |
| Authors: |
| MALKAN, M.A. |
| Affiliation: |
| AA(California Institute of Technology, Pasadena, CA) |
| Journal: |
| IN: Quasars and gravitational lenses; Proceedings of the Twenty-fourth Liege International Astrophysical Colloquium, Cointe-Ougree, Belgium, June 21-24, 1983 (A85-13301 03-90). Cointe-Ougree, Belgium, Universite de Liege, 1983, p. 433-436. |
| Publication Date: |
| 06/1983 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ACCRETION DISKS, CONTINUOUS SPECTRA, QUASARS, SEYFERT GALAXIES, ULTRAVIOLET ASTRONOMY, ULTRAVIOLET SPECTRA, ASTRONOMICAL MODELS, GALACTIC NUCLEI |
| Bibliographic Code: |
| 1983qgl..conf..433M |
Abstract
For the last two decades, intensive studies have been conducted
regarding the continuous emission from quasars and the nuclei of Seyfert
1 galaxies. Observations over at least three frequency octaves are
needed for a meaningful analysis of the continuum. Recent satellite
observatories have made it possible to obtain the required data.
However, some observational problems had to be overcome in connection
with the interpretation of the data. One of these problems is related to
the observation that the starlight in many Seyfert galaxies is often at
least as bright as the nonstellar continuum emitted in their nuclei. In
the case of a few Seyfert 1 galaxies, such as Markarian 231, a study of
the intrinsic continuum is virtually impossible, because the galaxies
are heavily reddened. Questions regarding the accretion disk hypothesis
are discussed, and observations which are crucial to an understanding of
the accretion process are considered.
| Title: |
| Infrared spectrophotometry of three Seyfert galaxies and 3C 273 |
| Authors: |
| CUTRI, R. M.; PUETTER, R. C.; RUDY, R. J.; WILLNER, S. P.; AITKEN, D. K.; JONES, B.; MERRILL, K. M.; ROCHE, P. F.; RUSSELL, R. W.; SOIFER, B. T. |
| Affiliation: |
| AD(California, University, La Jolla, Calif.) AE(Anglo-Australian Observatory, Epping, New South Wales, Australia; University College, London, England) AF(California, University, La Jolla, Calif.; Minnesota, University, Minneapolis, Minn.) AG(Minnesota, University, Minneapolis, Minn.) AH(University College, London, England) AI(California, University, La Jolla, Calif.; Cornell University, Ithaca, N.Y.) AJ(California, University, La Jolla; California Institute of Technology, Pasadena, Calif.) |
| Journal: |
| Astrophysical Journal, Part 1, vol. 245, May 1, 1981, p. 818-828. |
| Publication Date: |
| 05/1981 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTRONOMICAL PHOTOMETRY, GALACTIC RADIATION, INFRARED ASTRONOMY, INFRARED SPECTROSCOPY, QUASARS, SEYFERT GALAXIES, SPECTRUM ANALYSIS, BROADBAND, EMISSION SPECTRA, INFRARED SPECTROPHOTOMETERS, LIGHT CURVE, LINE SPECTRA, SPECTRAL ENERGY DISTRIBUTION, STELLAR RADIATION, STELLAR SPECTRA |
| Bibliographic Code: |
| 1981ApJ...245..818C |
Abstract
Spectrophotometry in the range 2.1-4.0 microns is presented for the
Seyfert galaxies NGC 1068, NGC 4151 and Mrk 231 and the quasar 3C 273,
together with broadband and narrowband observations of the Seyfert
galaxies in the range 8-13 microns. The spectra of NGC 1068 and NGC 4151
are found to contain a significant component due to starlight,
especially at shorter wavelengths. The nonstellar component in NGC 1068
is observed to fall off rapidly at wavelengths shorter than 4 microns,
consistent with the interpretation of the excess beyond 5 microns as
thermal reradiation by dust. Observations confirm the variability of NGC
4151, and indicate the presence of two components of the flux other than
starlight: a nonthermal variable component predominant at shorter
wavelengths and a constant, probably thermal component at wavelengths
greater than 3 microns. Mrk 231 and 3C 273 exhibit no discernable
stellar component and were not observed to vary by more than 10%.
Evidence is obtained for a broad minimum in the 8 to 13 micron spectrum
of Mrk 231, as well as possible structure between rest wavelengths of
2.8 and 2.9 microns, and the spectrum is not a power law. The spectrum
of 3C 273 is consistent with a power law from 1.2 to 10 microns, with
small but significant deviations.
| Title: |
| OPTICAL POLARIZATION OF SEYFERT GALAXIES. |
| Authors: |
| THOMPSON, HAROLD IAN BRUCE |
| Affiliation: |
| THE UNIVERSITY OF WESTERN ONTARIO (CANADA). |
| Journal: |
| Thesis (PH.D.)--THE UNIVERSITY OF WESTERN ONTARIO (CANADA), 1980.Source: Dissertation Abstracts International, Volume: 41-12, Section: B, page: 4554. |
| Publication Date: |
| 00/1980 |
| Category: |
| Physics: Astronomy and Astrophysics |
| Origin: |
| UMI |
| Abstract Copyright: |
| (c) 1980: UMI Company |
| Bibliographic Code: |
| 1980PhDT........59T |
Abstract
The optical flux from the nuclei of many Seyfert galaxies is linearly
polarized. There are various mechanisms which must be considered as
possible sources of the polarization (e.g. direct synchrotron radiation,
dust scattering, electron scattering, transmission through aligned dust
grains). Determining the source of the polarization in Seyfert galaxies
requires data on the continuum polarization spectra as well as data on
the polarization of the emission lines. Observations of the linear
polarization of the Seyfert galaxies Mrk 3, Mrk 231, Mrk 509, NGC 3227,
NGC 3516, NGC 4151 and NGC 5548 are presented. Observations were made
with the University of Western Ontario photoelectric filter polarimeter
and with the Hale Observatories multichannel spectrophotometer, and
include data on the continuum, H(alpha) and {0 III} (lamda)5007
polarization. Additional data obtained with the Digicon
spectropolarimeter at Steward observatory and with the Steward filter
polarimeter are included for discussion from Thompson et al. 1979, 1980.
The intrinsic polarization of the emission lines is derived and compared
to the adjacent continuum values. The continuum polarization and
position angle are investigated as a function of observing aperture
size, wavelength and time. These data are used in a discussion of
individual galaxies. The galaxies Mrk 3, Mrk 231, NGC 3227 and NGC 3516
show continuum polarization which increases smoothly into the blue and
have polarized H(alpha) emission, indicating dust scattering as the
source of the polarization. The galaxies Mrk 509, NGC 4151 and NGC 5548
have unpolarized H(alpha) emission and the continuum polarization drops
into the UV from the blue. This drop in polarization is identified with
the diluting effects of the Balmer continuum, and correction for this
produces a continuum polarization spectrum similar to the other galaxies
for Mrk 509 and NGC 4151. This suggests that dust scattering might be
important in Mrk 509 and NGC 4151. If the polarization in Mrk 509 and
NGC 4151 is produced by synchrotron emission then the observed
polarization spectra indicate that a large fraction of the continuum
flux is in the form of starlight. Comparisons are made between the
polarization spectra and the B-V and B-10(mu) colours and the
H(alpha)/H(beta) ratio. Objects with unpolarized H(alpha) emission tend
to have bluer colours, flatter polarization spectra and lower
H(alpha)/H(beta) ratios, consistent with the polarization being produced
by dust scattering. The presence of dust in Seyfert nuclei is indicated
by a correlation between the B-10(mu) colour and the H(alpha)/H(beta)
ratio.
| Title: |
| POLARIZATION OF SEYFERT GALAXIES AND RELATED OBJECTS. |
| Authors: |
| MAZA SANCHO, JOSE |
| Affiliation: |
| UNIVERSITY OF TORONTO (CANADA). |
| Journal: |
| Thesis (PH.D.)--UNIVERSITY OF TORONTO (CANADA), 1979.Source: Dissertation Abstracts International, Volume: 41-02, Section: B, page: 0596. |
| Publication Date: |
| 00/1979 |
| Category: |
| Physics: Astronomy and Astrophysics |
| Origin: |
| UMI |
| Abstract Copyright: |
| (c) 1979: UMI Company |
| Bibliographic Code: |
| 1979PhDT.......127M |
Abstract
A survey of the optical polarization of 47 Seyfert galaxies is
presented. It was found that more than 80% of the Seyfert (Sy) galaxies
have optical polarizations less than 1.5%; more than 70% have a
polarization less than 1%. Three new highly polarized objects were
discovered: Markarian (Mrk) 376, Mrk 486 and IC 4329A. Highly polarized
objects occur more frequently among Sys than among quasars. The
frequency distribution of intrinsic polarization is obtained after
corrections for interstellar polarization in our Galaxy and the effect
of dilution by starlight of the underlying galaxy. The distribution of
this "normalized", redshift-independent polarization has a peak at a low
value of 0.8%. Allowing for the standard dilution, the light from
Seyfert nuclei seems to be more polarized than that of QSOs, perhaps due
to dust in Sy nuclei. The application of Sandage's two component model
for N galaxies to Sy nuclei is discussed in some detail including the
effect of intrinsic reddening in the nucleus. The probability of finding
a large polarization among Sy galaxies increases for bluer Sy1s and for
redder Sy2s, suggestive of a non-thermal origin for the polarization of
Sy1s and polarization produced by dust in Sy2s. The average polarization
and its dispersion increase with increasing Balmer decrement. The
infrared, X-ray and radio properties of the galaxies, the presence of Fe
line emission, and the optical morphology are compared with their
polarization properties but no correlations are seen.
Wavelength-dependent polarization is found in most strongly polarized
objects. A correlation is found between the steepness of the wavelength
dependence and the (U-B)o color of the galaxy, which could be
interpreted as the effects of varying amounts of dilution of the nuclear
light by the host galaxies. On the other hand, if the polarization is
produced by aligned dust particles, they should be from 2 to 5 times
smaller than normal grains in our Galaxy. Spectropolarimetry of other
galaxies implies polarization by scattering off dust clouds. Three-sigma
upper limits for percentage circular polarization are as follows: Mrk 3
(0.07), Mrk 231 (0.07), Mrk 376 (0.3), N 1275 (0.03), IC 4329A (0.2),
and M 82 (0.03). The most interesting objects are discussed
individually. Tentative conclusions concerning the origin of the
polarization in Sy galaxies are: (i) There are a few exceptional cases
of strong polarization of non-thermal origin (N 1275 and possibly Mrk
486). (ii) Dust is responsible for strong polarization in a few objects
(N 1068, Mrk 376, and IC 4329A). (iii) Strongly polarized objects are
more common among Sys than quasars. (iv) Most Sys have a low
polarization, which does not by itself argue against the presence of a
non-thermal source of continuum radiation, since even quasars have a
characteristically low polarization. Appendix A presents the results of
a program to monitor the optical polarization of N 1275 and several BL
Lacertae objects. Variability on time-scales as small as 10 hours was
found. A lower limit, 7 x 10('8) M(,(CIRCLE)), to the mass of a black
hole powering the nucleus is obtained. The extremely rapid variability
of OI-090.4 and OJ-131 leads indirectly to upper limits for their
redshifts, 0.11 and 0.18 respectively. Appendix B presents a detailed
analysis of the wavelength dependence of the optical polarization of the
BL Lacertae objects Mrk 421 and Mrk 501.
| Title: |
| High frequency radio observations of Seyfert galaxies |
| Authors: |
| MCCUTCHEON, W. H.; GREGORY, P. C. |
| Affiliation: |
| AB(British Columbia, University, Vancouver, Canada) |
| Journal: |
| Astronomical Journal, vol. 83, June 1978, p. 566-573. Research supported by the National Research Council of Canada. |
| Publication Date: |
| 06/1978 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| GALACTIC RADIATION, HIGH FREQUENCIES, RADIO ASTRONOMY, SEYFERT GALAXIES, INTERSTELLAR MAGNETIC FIELDS, LUMINOUS INTENSITY, MAGNETIC FLUX, TABLES (DATA) |
| Bibliographic Code: |
| 1978AJ.....83..566M |
Abstract
Observations have been made of 42 galaxies (40 Seyferts, one BL Lac-type
galaxy, and one emission-line galaxy) at wavelengths of 2.8 and 1.3 cm.
Twenty were detected at one or both frequencies, and spectra are
presented for 14 of these using the present and previously published
data. Seven, and possibly nine, have power-law spectra. The remaining
spectra are more complex. Four galaxies show variability at one of the
frequencies. Two of them, Mrk 348 and Mrk 231 vary on a time scale of a
few days at a wavelength of 1.30 cm. The radio luminosities, calculated
for 18 galaxies, cover a range extending from the normal spirals at the
low end to the quasars at the high end. The Seyferts with radio
luminosities greater than 10 to the 42nd power ergs/s are predominantly
Class 1, whereas those with values less than 10 to the 42nd power ergs/s
belong to both Class 1 and Class 2.
| Title: |
| Material in the vicinity of galaxies |
| Authors: |
| BURKE, B. F. |
| Affiliation: |
| AA(MIT, Cambridge, Mass.) |
| Journal: |
| In: Structure and properties of nearby galaxies; Proceedings of the Symposium, Bad Muenstereifel, West Germany, August 22-26, 1977. (A79-13481 03-90) Dordrecht, D. Reidel Publishing Co., 1978, p. 287-290; Discussion, p. 291, 292. |
| Publication Date: |
| 00/1978 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ABSORPTION SPECTRA, GALACTIC RADIO WAVES, INTERGALACTIC MEDIA, RADIO SPECTRA, EMISSION SPECTRA, HYDROGEN CLOUDS, LINE SPECTRA, QUASARS |
| Bibliographic Code: |
| 1978IAUS...77..287B |
Abstract
Observational evidence for the presence of outlying clouds of neutral
hydrogen in the vicinity of galaxies is discussed. Reference is made to
previous detections of absorption lines corresponding to outlying
neutral hydrogen clouds associated with the galaxies NGC 3067, Markarian
6 (IC 450) in the cluster Zw 0642.0+7334, Markarian 1 (NGC 447),
Markarian 231, Markarian 3, 3C 178, and the Magellanic Clouds. It is
noted that the observed absorption lines generally imply column
densities of between 10 to the 20th and 10 to the 21st power per sq cm
for a state temperature of 100 K and are probably situated at some
distance from the nuclei of the galaxies. The origin of these outlying
hydrogen clouds is considered, and at least three modes of genesis are
taken to be feasible: tidal interaction, expulsion by activity in a
galactic nucleus, and accretion from the intergalactic or intracluster
medium.
| Title: |
| Seyfert galaxies with large z - An electronographic survey |
| Authors: |
| WEHINGER, P. A.; WYCKOFF, S. |
| Affiliation: |
| AB(Royal Greenwich Observatory, Herstmonceux, Sussex, England) |
| Journal: |
| Royal Astronomical Society, Monthly Notices, vol. 181, Oct. 1977, p. 211-231. Research supported by the Science Research Council and Smithsonian Research Foundation. |
| Publication Date: |
| 10/1977 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| ASTRONOMICAL MAPS, ELECTRONOGRAPHY, SEYFERT GALAXIES, SPIRAL GALAXIES, ASTRONOMICAL PHOTOGRAPHY, GALACTIC STRUCTURE, ISOPHOTES, PHOTOGRAPHIC PLATES, RESOLUTION |
| Bibliographic Code: |
| 1977MNRAS.181..211W |
Abstract
Electronographic observations (3500-7500 A) of Seyfert galaxies in the
range z = 0.022-0.057 are presented in the form of isophotal maps which
attain levels of detection not previously reported for these galaxies.
The observations include high-resolution isophotal maps of: Markarian
79, 110, 124, 141, 176, 198, 231, 268, 273, 471, 474, 506, and 501 (a BL
Lac-type object). The weakest contours attain intensity levels estimated
to be 15 percent the sky background (B of approximately 24.5 mag/sq
arcsec). Both fine-resolution (about 1 arcsec) and coarse-resolution
(approximately 4 arcsec) maps are presented for each object. The
majority of the sample (about 60 percent) are probably spiral galaxies,
while most of the remainder have jets or other disturbed features.
| Title: |
| 3-millimeter and infrared continuum observations of Markarian galaxies |
| Authors: |
| JOYCE, R. R.; SIMON, M. |
| Journal: |
| Astronomical Society of the Pacific, Publications, vol. 88, Dec. 1976-Jan. 1977, p. 870-873. NSF-supported research. |
| Publication Date: |
| 12/1976 |
| Category: |
| Astrophysics |
| Origin: |
| STI |
| NASA/STI Keywords: |
| CONTINUOUS SPECTRA, GALACTIC RADIATION, INFRARED SPECTRA, MARKARIAN GALAXIES, MILLIMETER WAVES, MICROWAVE SPECTRA, RADIO ASTRONOMY, RADIO GALAXIES |
| Bibliographic Code: |
| 1976PASP...88..870J |
Abstract
Recent 3.2-mm and infrared observations of the Markarian galaxies 3, 11,
171, 231, 348, 421, and 501 are reported. Ma 348, Ma 421, and Ma 501
were detected at 93 GHz. The observations of all these sources at 93 GHz
are generally consistent with the longer-wavelength radio data of
Kojoian et al. (1976). The infrared spectra of these objects are diverse
and complex, and are not strikingly correlated with their radio
behavior. The long-wavelength infrared spectra of Ma 3, Ma 171, and Ma
231 are quite similar.
| Title: |
| The radio brightness distribution of eight Markarian galaxies |
| Authors: |
| SRAMEK, R. A.; TOVMASSIAN, H. M. |
| Affiliation: |
| AA(National Astronomy and Ionosphere Center, Arecibo, P.R.) AB(Biurakanskaia Astrofizicheskaia Observatoriia, Yerevan, Armenian SSR) |
| Journal: |
| Astrophysical Journal, vol. 207, Aug. 1, 1976, pt. 1, p. 725-729, 731, 733, 735. |
| Publication Date: |
| 08/1976 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| GALACTIC RADIATION, LUMINOUS INTENSITY, MARKARIAN GALAXIES, RADIO SOURCES (ASTRONOMY), SEYFERT GALAXIES, GALACTIC NUCLEI, SPECTRAL ENERGY DISTRIBUTION, ULTRAVIOLET RADIATION |
| Bibliographic Code: |
| 1976ApJ...207..725S |
Abstract
Results of radio aperture-synthesis observations at 2.7 and 8.1 GHz are
given for eight Markarian galaxies. Five of these galaxies are
Seyfert-type objects (MRK 1, 3, 231, 273, and 348) and one is a BL
Lacertae object (MRK 501); these exhibit only an unresolved radio
nucleus. Two other galaxies show an extended source (MRK 297) and a
double source inside the optical image (MRK 171). This double source
coincides with optically bright regions that are off-center with respect
to the general outline of the galaxy.
| Title: |
| Measurements of galactic nuclei at 34 microns |
| Authors: |
| RIEKE, G. H.; LOW, F. J. |
| Affiliation: |
| AA(Steward Observatory, Tucson, Ariz.) AB(Arizona, University, Tucson, Ariz.) |
| Journal: |
| Astrophysical Journal, vol. 200, Sept. 1, 1975, pt. 2, p. L67-L69. NSF-supported research. |
| Publication Date: |
| 09/1975 |
| Category: |
| Astronomy |
| Origin: |
| STI |
| NASA/STI Keywords: |
| FAR INFRARED RADIATION, GALACTIC NUCLEI, INFRARED ASTRONOMY, LUMINOUS INTENSITY, ANGULAR RESOLUTION, ATMOSPHERIC WINDOWS, EMISSION SPECTRA, INFRARED SPECTRA, LINE SPECTRA, POWER SPECTRA, RADIATION MEASUREMENT, SEYFERT GALAXIES, TELESCOPES |
| Bibliographic Code: |
| 1975ApJ...200L..67R |
Abstract
Results are reported for IR observations of the nuclei of NGC 1275, NGC
4151, Markarian 231, NGC 5195, and NGC 5253 which were made at 34
microns with the NASA 61-inch telescope. The total luminosity of these
sources is estimated, and it is found that the total luminosity of
Markarian 231 is nearly 10 trillion times that of the sun. It is noted
that this power output lies within the luminosity range of quasars.
| Title: |
| Submillimeter Observations of the Ultraluminous Broad Absorption Line Quasar APM 08279+5255 |
| Authors: |
| LEWIS, GERAINT F.; CHAPMAN, SCOTT C.; IBATA, RODRIGO A.; IRWIN, MICHAEL J.; TOTTEN, EDWARD J. |
| Journal: |
| Astrophysical Journal Letters v.505, p.L1 |
| Publication Date: |
| 09/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| COSMOLOGY: GRAVITATIONAL LENSING, INFRARED: GALAXIES, GALAXIES: QUASARS: INDIVIDUAL ALPHANUMERIC: APM 08279+5255 |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...505L...1L |
Abstract
With an inferred bolometric luminosity of 5x10^{15} Lsolar, the recently
identified z=3.87 , broad absorption line quasar APM 08279+5255 is
apparently the most luminous object currently known. Since half of its
prodigious emission occurs in the infrared, APM 08279+5255 also
represents the most extreme example of an ultraluminous infrared galaxy.
Here we present new submillimeter observations of this phenomenal
object; while indicating that a vast quantity of dust is present, these
data prove to be incompatible with the current models of emission and
reprocessing mechanisms in ultraluminous systems. The influence of
gravitational lensing on these models is considered, and we find that
while the emission from the central continuum-emitting region may be
significantly enhanced, lensing-induced magnification cannot easily
reconcile the models with the observations. We conclude that further
modeling, including the effects of any differential magnification, is
required to explain the observed emission from APM 08279+5255.
| Title: |
| Infrared Space Observatory Measurements of a [C II] 158 Micron Line Deficit in Ultraluminous Infrared Galaxies |
| Authors: |
| LUHMAN, M. L.; SATYAPAL, S.; FISCHER, J.; WOLFIRE, M. G.; COX, P.; LORD, S. D.; SMITH, H. A.; STACEY, G. J.; UNGER, S. J. |
| Journal: |
| Astrophysical Journal Letters v.504, p.L11 |
| Publication Date: |
| 09/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: ISM, GALAXIES: STARBURST, INFRARED: GALAXIES, INFRARED: ISM: LINES AND BANDS, ISM: ATOMS |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...504L..11L |
Abstract
We report measurements of the [C II] 157.74 mu m fine-structure line in
a sample of seven ultraluminous infrared galaxies (ULIGs) (
L_{{IR}}>10^{12} Lsolar) with the Long Wavelength Spectrometer on the
Infrared Space Observatory. The [C II] line is an important coolant in
galaxies and arises in interstellar gas exposed to far-ultraviolet
photons ( h nu >=11.26 eV); in ULIGs, this radiation stems from the
bursts of star formation and/or from the active galactic nuclei that
power the tremendous infrared luminosity. The [C II] 158 mu m line is
detected in four of the seven ULIGs; the absolute line flux (about a few
times 10-20 W cm-2) represents some of the faintest extragalactic[C II]
emission yet observed. Relative to the far-infrared continuum, the [C
II] flux from the observed ULIGs is ~10% of that seen from nearby normal
and starburst galaxies. We discuss possible causes for the [C II]
deficit, namely (1) self-absorbed or optically thick [C II] emission,
(2) saturation of the [C II] emission in photodissociated gas with high
gas density n ( >>3x10^{3} cm-3) or with a high ratio of incident UV
flux G0 to n ( G_{0}/n>~10 cm3), or (3) the presence of a soft
ultraviolet radiation field caused, for example, by a stellar population
deficient in massive main-sequence stars. As nearby examples of
colliding galaxies, ULIGs may resemble high-redshift protogalaxies in
both morphology and spectral behavior. If true, the suggested [C II]
deficit in ULIGs poses limitations on the detection rate of high-z
sources and on the usefulness of [C II] as an eventual tracer of
protogalaxies.
| Title: |
| Extensive Spiral Structure and Corotation Resonance |
| Authors: |
| CANZIAN, BLAISE |
| Journal: |
| Astrophysical Journal v.502, p.582 |
| Publication Date: |
| 08/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: KINEMATICS AND DYNAMICS, GALAXIES: SPIRAL, GALAXIES: STRUCTURE |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...502..582C |
Abstract
Spiral density wave theories demand that grand-design spiral structure
be bounded, at most, between the inner and outer Lindblad resonances of
the spiral pattern. The corotation resonance lies between the outer and
the inner Lindblad resonances. The locations of the resonances are at
radii whose ratios to each other are rather independent of the shape of
the rotation curve. The measured ratio of outer to inner extent of
spiral structure for a given spiral galaxy can be compared to the
standard ratio of corotation to inner Lindblad resonance radius. In the
case that the measured ratio far exceeds the standard ratio, it is
likely that the corotation resonance is within the bright optical disk.
Studying such galaxies can teach us how the action of resonances sculpts
the appearance of spiral disks. This paper reports observations of 140
disk galaxies, leading to resonance ratio tests for 109 qualified spiral
galaxies. It lists candidates that have a good chance of having the
corotation resonance radius within the bright optical disk.
| Title: |
| A Radio Millihalo in the Nucleus of NGC 1275 |
| Authors: |
| SILVER, C. S.; TAYLOR, G. B.; VERMEULEN, R. C. |
| Journal: |
| Astrophysical Journal v.502, p.229 |
| Publication Date: |
| 07/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: INDIVIDUAL NGC NUMBER: NGC 1275, GALAXIES: JETS, RADIO CONTINUUM: GALAXIES, GALAXIES: NUCLEI, GALAXIES: HALOS |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...502..229S |
Abstract
We present high dynamic range (20,000:1 at 1414 MHz) VLBA observations
of NGC 1275 (3C 84) at 1414, 612, and 330 MHz. With these observations,
we have discovered a previously undetected counterjet component located
~80 mas (20 h-1 pc) to the north of the compact core. This counterjet
component, like those closer in to the nucleus, appears to be free-free
absorbed. We have also discovered the first radio halo around an active
galactic nucleus on small (<1 kpc) scales. This millihalo cannot be the
result of scattering and is most likely produced by synchrotron
radiation from relativistic particles that have diffused out from the
parsec-scale jets over the lifetime of 3C 84.
| Title: |
| Central Activity in the Barred Galaxy NGC 3367 |
| Authors: |
| GARCÍA-BARRETO, J. A.; RUDNICK, L.; FRANCO, J.; MARTOS, M. |
| Affiliation: |
| AA(Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 70-264, 04510 México, D.F., Mexico), AB(Department of Astronomy, University of Minnesota, 116 Church Street, SE, Minneapolis, MN 55455), AD(Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 70-264, 04510 México D.F., Mexico) |
| Journal: |
| The Astronomical Journal, Volume 116, Issue 1, pp. 111-118. |
| Publication Date: |
| 07/1998 |
| Origin: |
| AJ |
| AJ Keywords: |
| GALAXIES: CLUSTERS: INDIVIDUAL (NGC 3367), GALAXIES: STRUCTURE, GALAXIES: INTERGALACTIC MEDIUM, GALAXIES: QUASARS: EMISSION LINES |
| Abstract Copyright: |
| The American Astronomical Society |
| Bibliographic Code: |
| 1998AJ....116..111G |
Abstract
We report the radio continuum structure of the barred galaxy NGC 3367
with an angular resolution of ~4.5". The radio structure indicates
emission from the disk and from a triple source consisting of the
nucleus straddled by two extended sources (the lobes). The triple source
shows an excess of radio continuum emission compared with the emission
expected from the total radio-Halpha correlation, suggesting a
nonthermal origin probably related to activity of an active galactic
nucleus (AGN) and not to star formation processes. The triple source is
approximately 12 kpc in extent at P.A. ~ 40 deg, close to (but not
aligned with) that of the stellar bar, P.A. ~ 65 deg. Only the southwest
lobe is polarized. The polarization asymmetry between the two lobes
suggests that the triple-source axis is slightly out of the plane. If
the origin of the emission is an outflow of plasma from an AGN, as seen
in weak radio galaxies and NGC 1068, then NGC 3367 provides an excellent
laboratory object to study a possible interaction of the ejected
material and the barred galaxy.
| Title: |
| The radio properties of radio-quiet quasars |
| Authors: |
| KUKULA, MAREK J.; DUNLOP, JAMES S.; HUGHES, DAVID H.; RAWLINGS, STEVE |
| Affiliation: |
| AA(Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA), AB(Institute for Astronomy, Department of Physics and Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ), AC(Institute for Astronomy, Department of Physics and Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ), AD(Department of Astrophysics, Nuclear &38; Astrophysics Laboratory, University of Oxford, Keble Road, Oxford OX1 3RH) |
| Journal: |
| Monthly Notices of the Royal Astronomical Society, Volume 297, Issue 2, pp. 366-382. |
| Publication Date: |
| 06/1998 |
| Origin: |
| MNRAS |
| MNRAS Keywords: |
| GALAXIES: ACTIVE, QUASARS: GENERAL, RADIO CONTINUUM: GALAXIES |
| Abstract Copyright: |
| (c) 1998 The Royal Astronomical Society |
| Bibliographic Code: |
| 1998MNRAS.297..366K |
Abstract
Although radio-quiet quasars (RQQs) constitute >~90 per cent of
optically identified quasar samples, their radio properties are only
poorly understood. In this paper we present the results of a
multi-frequency VLA study of 27 low-redshift RQQs. We detect radio
emission from 20 objects, half of which are unresolved (<=0.24 arcsec).
In cases where significant structure can be resolved, double, triple and
linear radio sources on scales of a few kpc are found. The radio
emission (typically) has a steep spectrum (alpha~0.7, where
S~nu^-alpha), and high brightness temperatures (T_B>=10^5 K) are
measured in some of the radio components. The RQQs form a natural
extension to the radio luminosity-absolute magnitude distribution of
nearby Seyfert 1s. We conclude that a significant fraction of the radio
emission in RQQs originates in a compact nuclear source directly
associated with the quasar. There are no significant differences between
the radio properties of RQQs with elliptical hosts and those in disc
galaxies within the current sample.
| Title: |
| A Study of External Galaxies Detected by the COBE Diffuse Infrared Background Experiment |
| Authors: |
| ODENWALD, STEN; NEWMARK, JEFFREY; SMOOT, GEORGE |
| Journal: |
| Astrophysical Journal v.500, p.554 |
| Publication Date: |
| 06/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| COSMOLOGY: DIFFUSE RADIATION, ISM: DUST, EXTINCTION, GALAXIES: ISM, GALAXIES: PHOTOMETRY, INFRARED: GALAXIES, SURVEYS |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...500..554O |
Abstract
A comparison of the COBE 1 Diffuse Infrared Background Experiment
(DIRBE) all-sky survey with the locations of known galaxies in the IRAS
Catalog of Extragalactic Objects and the Center for Astrophysics Catalog
of Galaxies led to the detection of as many as 57 galaxies. In this
paper, we present the photometric data for these galaxies and an
analysis of the seven galaxies that were detected at lambda > 100 mu m.
Estimates of the ratio of the mass of the cold dust (CD) component
detected at Td = 20-30 K to a very cold dust (VCD) component with Td ~
10-15 K suggest that between 2%-100% of the cirrus-like CD mass can also
exist in many of these galaxies as VCD. In one galaxy, M33, the DIRBE
photometry at 240 mu m suggests as much as 26 times as much VCD may be
present as compared to the cirrus-like component. Further submillimeter
measurements of this galaxy are required to verify such a large
population of VCD. We also present 10 galaxies that were detected in the
sky region not previously surveyed by IRAS and that can be used to
construct a flux-limited all-sky catalog of galaxies brighter than 1000
Jy with a modest completeness limit of about 65%.
| Title: |
| What Powers Ultraluminous IRAS Galaxies? |
| Authors: |
| GENZEL, R.; LUTZ, D.; STURM, E.; EGAMI, E.; KUNZE, D.; MOORWOOD, A. F. M.; RIGOPOULOU, D.; SPOON, H. W. W.; STERNBERG, A.; TACCONI-GARMAN, L. E.; TACCONI, L.; THATTE, N. |
| Journal: |
| Astrophysical Journal v.498, p.579 |
| Publication Date: |
| 05/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: STELLAR CONTENT, GALAXIES: STARBURST, GALAXIES: NUCLEI, INFRARED: GALAXIES |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...498..579G |
Abstract
We present an ISO SWS and ISOPHOT-S, mid-infrared spectroscopic survey
of 15 ultraluminous IRAS galaxies (LIR >= 1012 L&sun;). We combine the
survey results with a detailed case study, based on arcsecond
resolution, near-IR, and millimeter imaging spectroscopy, of one of the
sample galaxies (UGC 5101). We compare the near- and mid-IR
characteristics of these ultraluminous galaxies to ISO and literature
data of 30 starburst and active galactic nuclei (AGN) template galaxies.
We find the following: 1. Of the ultraluminous IRAS galaxies in our
sample, 70%-80% are predominantly powered by recently formed massive
stars, and 20%-30% are powered by a central AGN. These conclusions are
based on a new infrared "diagnostic diagram" involving the ratio of
high- to low-excitation mid-IR emission lines on the one hand, and the
strength of the 7.7 mu m PAH feature on the other hand. 2. At least half
of the sources probably have simultaneously an active nucleus and
starburst activity in a 1-2 kpc diameter circumnuclear disk/ring. 3. The
mid-IR emitting regions are highly obscured [Av(screen) ~ 5-50 or
Av(mixed) ~ 50-1000]. In a model where star-forming regions and dense
molecular clouds are fully mixed, the ISO-derived, V-band dust
extinctions approach the dust column densities inferred from CO
millimeter measurements. After correction for these extinctions, we
estimate that the star-forming regions in ultraluminous infrared
galaxies have ages between 107 and 108 yr, similar to but somewhat
larger than those found in lower luminosity starburst galaxies. 4. In
the sample we have studied there is no obvious trend for the AGN
component to dominate in the most compact, and thus most advanced
mergers. Instead, at any given time during the merger evolution, the
time-dependent compression of the circumnuclear interstellar gas, the
accretion rate onto the central black hole, and the associated radiation
efficiency may determine whether star formation or AGN activity
dominates the luminosity of the system.
| Title: |
| Millimeter-wave thermal dust emission from luminous mergers |
| Authors: |
| BRAINE, J.; DUMKE, M. |
| Affiliation: |
| AA(Observatoire de Bordeaux, URA 352, CNRS/INSU, B.P. 89, F-33270 Floirac, France), AB(Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn, Germany; Institut de Radioastronomie Millimetrique, 300 rue de la Piscine, F-38406 St. Martin d'Heres Cedex, France) |
| Journal: |
| Astronomy and Astrophysics, v.333, p.38-42 (1998) |
| Publication Date: |
| 05/1998 |
| Origin: |
| A&A |
| A&A Keywords: |
| GALAXIES: INDIVIDUAL: MKN 231, NGC 520, NGC 6240, ARP 299, GALAXIES: ISM, RADIO CONTINUUM: GALAXIES |
| Abstract Copyright: |
| (c) 1998: Astronomy & Astrophysics |
| Bibliographic Code: |
| 1998A&A...333...38B |
Abstract
We have observed several infrared-luminous galaxies which are in the
process of merging (Mkn 231, Arp 299, NGC 6240, NGC 520, and IRAS
17208-0014) at 1.2mm with the multi-channel bolometer at the IRAM
30-meter telescope. Such observations of the long-wavelength thermal
dust emission provide an alternative to CO as a measure of the gas
mass.
Comparing the masses of gas determined from the dust emission and from
CO observations of these galaxies, we find that the conversion factor
N(H_2) / I_CO(1-0) < 0.5 10^{20} \cm2 (\K\kms)^{-1}. Our calculations
are conservative. We have chosen a \nu^2 emissivity; other emission laws
result in higher dust temperatures. We have made our calculations
assuming a metallicity of 2 Z_\odot$, which is low for a galactic
nucleus. We have not assumed any enhancement of the dust emission
through agglomeration of dust particles nor destruction of grains.
Finally, we have assumed that all of the gas associated with 1.2mm
thermal dust emission is molecular. Expected deviations from these
assumptions would all decrease the gas masses estimated from the thermal
dust emission, resulting in even lower values for the N(H_2) / I_CO
conversion factor.
| Title: |
| A CCD Study of the Environment of Seyfert Galaxies. I. The Survey |
| Authors: |
| DE ROBERTIS, M. M.; HAYHOE, K.; YEE, H. K. C. |
| Journal: |
| Astrophysical Journal Supplement v.115, p.163 |
| Publication Date: |
| 04/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: FORMATION, GALAXIES: INTERACTIONS, GALAXIES: PHOTOMETRY, GALAXIES: SEYFERT |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJS..115..163D |
Abstract
Large-format, R-band CCD data are presented for a spectroscopically
complete sample of 34 Seyfert galaxies and a control sample of 45
nonactive galaxies that are well matched to the Seyfert sample in
redshift, luminosity, and morphological type. Gray-scale images of the
local environment are included for all of the host galaxies, as well as
figures showing the surface brightness, ellipticity, and position angle
of the major axis as a function of radius. These data will be used to
study the environments of these galaxies and hence to test the
"interaction hypothesis" that, over the past two decades, has been
implicated as the triggering mechanism for nuclear activity. While there
are no dramatic differences in most parameters between the active and
nonactive samples, the distributions of ellipticities and major-axis
position-angle excursions of the Seyfert host galaxies and the control
galaxies are marginally different. A higher proportion of Seyfert
galaxies appear to be involved in late-stage mergers. A similar fraction
of the control sample, however, displays significant light asymmetries
that could be evidence for recent interactions. Moreover, a small but
substantial number of the Seyfert galaxies show no evidence for recent
interactions as judged by the absence of light asymmetries.
| Title: |
| A Subparsec Radio Jet or Disk in NGC 4151 |
| Authors: |
| ULVESTAD, JAMES S.; ROY, ALAN L.; COLBERT, EDWARD J. M.; WILSON, ANDREW S. |
| Journal: |
| Astrophysical Journal v.496, p.196 |
| Publication Date: |
| 03/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: INDIVIDUAL NGC NUMBER: NGC 4151, GALAXIES: JETS, GALAXIES: SEYFERT, RADIO CONTINUUM: GALAXIES |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...496..196U |
Abstract
We have imaged the classical Seyfert galaxy NGC 4151 with the VLBA at
wavelengths of 6 and 18 cm, achieving resolutions of ~=2 and 5 mas
(~=0.16 and 0.40 pc), respectively. At 18 cm, four radio components,
spread over ~=0."5 (~=40 pc) are detected. The easternmost pair
comprises a bright component elongated in position angle ~=20 deg
(component E) and an extension to the northeast (component F) which
curves into position angle ~=75 deg, similar to that of the 3."5 (280
pc) scale radio jet and the narrow-line region. At the higher resolution
achieved at 6 cm, component E is found to be a linear radio source with
a length of ~13 mas (1.0 pc). This source has a length/width ratio of
>~4, and therefore fulfills one of the classical criteria for a radio
jet, but its radio luminosity is only ~1038 ergs s-1, several orders of
magnitude less than the parsec-scale jets in radio galaxies. It is also
misaligned by ~=55 deg from the arcsecond-scale radio jet. Possible
reasons for the misalignment include deflection by the inner narrow-line
region, buoyancy forces, and a change in the plane of the accretion disk
presumably responsible for jet collimation. We also discuss an
alternative interpretation, in which component E is a disk or torus
viewed edge-on and emitting flat-spectrum, possibly thermal, radio
emission. Component E appears to be the only part of the radio emission
that contains a significant flat-spectrum component, and we favor
identification of the central, brightest, unresolved subcomponent of E
as the ultraviolet (UV) and optical nucleus. In order to reconcile the
much smaller column density of H I toward the nucleus found by Lyman
absorption than by 21 cm absorption measurements, we argue that a ~=0.01
pc thick gas disk surrounds the nucleus and is ionized out to a radius
of ~=2 pc. The large 21 cm absorption column observed then results from
off-nuclear radio components shining through the outer, neutral part of
this disk. The flat spectrum of the nuclear radio source may indicate
synchrotron self-absorption or free-free absorption by the inner,
ionized part of the accretion disk. Interestingly, the apparent nuclear
source and a radio subcomponent ~=0.2 pc to the southeast align
precisely perpendicular to the arcsec-scale radio jet, suggesting that
they may outline the large-scale structure of the accretion disk
responsible for jet collimation. Comparison of the 18 cm image with the
European VLBI network image acquired by Harrison et al. in 1984 provides
upper limits of 0.14c and 0.25c for the apparent speeds of the radio
components at distances of 7 and 36 pc, respectively, from the galaxy
nucleus.
| Title: |
| A CCD Study of the Environment of Seyfert Galaxies. II. Testing the Interaction Hypothesis |
| Authors: |
| DE ROBERTIS, M. M.; YEE, H. K. C.; HAYHOE, K. |
| Journal: |
| Astrophysical Journal v.496, p.93 |
| Publication Date: |
| 03/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: FORMATION, GALAXIES: INTERACTIONS, GALAXIES: SEYFERT, GALAXIES: STATISTICS |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...496...93D |
Abstract
An analysis of the environment of a sample of 33 CfA Seyfert galaxies
and a control sample of 45 nonactive galaxies matched in luminosity,
redshift, and morphology to the Seyfert galaxies as reported in Paper I
is presented. The covariance function amplitudes of the Seyfert and
control samples are not statistically significantly different from one
another and from the general field. Moreover, the companion frequency of
the Seyfert galaxies, the probability of finding a companion galaxy
brighter than -17.5 in R within 50 kpc (0.30 +/- 0.11), is not
statistically significantly different from that for the nonactive
control sample (0.23 +/- 0.09). The mean environment of Seyfert 1
galaxies is found to be different from that of Seyfert 2 galaxies at
greater than the 95% confidence level, in the sense that the latter have
a larger covariance amplitude. Such evidence is problematic for the
Unified Model, which attributes spectroscopic differences between the
classes to purely geometric effects on the order of parsec scales. It
cannot, however, account for differences on the order of 100 kpc scales.
It is argued that triggering of activity in galactic nuclei may involve
a variety of mechanisms and may depend on the luminosity of the class.
That is, while there is excellent evidence that QSOs, radio galaxies,
and BL Lac objects inhabit environments significantly richer than the
field, the same does not seem to be true for Seyfert galaxies and
perhaps for LINERs. Finally, because a significant fraction of Seyfert
host galaxies show little or no evidence for a recent merger, it is
suggested that "minor mergers," mergers that involve a gas-rich disk
galaxy and a bound companion or satellite galaxy, may play a significant
role in triggering activity in Seyfert galaxies.
| Title: |
| An X-ray Luminous, Dwarf Seyfert Companion of Markarian 273 |
| Authors: |
| XIA, X.-Y.; BOLLER, TH.; WU, H.; DENG, Z.-G.; GAO, Y.; ZOU, Z.-L.; MAO, S.; BOERNER, G. |
| Journal: |
| Astrophysical Journal Letters v.496, p.L9 |
| Publication Date: |
| 03/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: INDIVIDUAL NAME: MARKARIAN 273, GALAXIES: NUCLEI, GALAXIES: SEYFERT, X-RAYS: GALAXIES |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...496L...9X |
Abstract
We report the discovery of the brightest X-ray source hosted by a faint
( M_{B}=-16 ) dwarf galaxy in the immediate vicinity of the
ultraluminous IRAS merging galaxy Markarian 273. The dwarf galaxy, 1.'3
away from Mrk 273, is at the tip of a faint northeast plume of Mrk 273.
Its spectrum exhibits strong [O III], H alpha , and [N II] emission
lines, which establish the redshift of the dwarf galaxy, z=0.0376 , the
same as that of Mrk 273. The emission-line ratios are typical of Seyfert
galaxies. The X-ray emission is consistent with a pointlike source
coincident with the center of the dwarf galaxy. The intrinsic X-ray
luminosity, 6.3x10^{41} ergs s ^{-1} , in the 0.1-2.4 keV energy range,
is about 7 times larger than the B-band luminosity. The X-ray spectrum
of the source can be fitted with a power law. All the evidence is
consistent with the source being a Seyfert galaxy. Out of ~10 faint
objects in the same field, only one is detected by ROSAT, and its ratio
of soft X-ray to optical luminosity is as high as those for BL Lacertae
objects and few active galactic nuclei (AGNs). If there is a population
of such dwarf AGNs hidden as companions of major merger galaxies (such
as Mrk 273), they may contribute to the luminosity function of AGNs and
the cosmic X-ray background at the faint end.
| Title: |
| A Near-Infrared Imaging Study of Seyfert Galaxies with Extended Emission-Line Regions |
| Authors: |
| ALONSO-HERRERO, ALMUDENA; SIMPSON, CHRIS; WARD, MARTIN J.; WILSON, ANDREW S. |
| Journal: |
| Astrophysical Journal v.495, p.196 |
| Publication Date: |
| 03/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: NUCLEI, GALAXIES: PHOTOMETRY, GALAXIES: SEYFERT, GALAXIES: STELLAR CONTENT, INFRARED: GALAXIES |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...495..196A |
Abstract
We present a near-infrared J-, H-, K-, and L'-band (1.25-3.80 mu m)
imaging study of a sample of Seyfert galaxies, including some of the
best studied examples of those with extended emission-line regions
(EELRs). The observed near-IR nuclear colors are consistent with a
mixture of emissions from an old stellar population and unreddened hot
dust. However, if the hot dust is located in the inner part of the dusty
torus invoked in unified schemes, the dust emission should suffer
substantial reddening. We show that the near-IR nuclear colors may also
be reproduced with a combination of emission from unreddened starlight
and hot (T = 1200 K) dust reddened by AV ~ 5-30 mag. All of the galaxies
exhibit an unresolved nuclear source at L'. The circumnuclear colors (in
a 0.5-1.0 kpc annulus) are similar to those of normal spiral galaxies in
most cases, although some galaxies exhibit extended emission at L',
presumably from hot dust, which causes the circumnuclear K - L' colors
to be redder than for normal galaxies. We argue that the circumnuclear
hot dust in NGC 1068 and NGC 4151 is probably heated by young stars. A
detailed study of the morphologies of the central and circumnuclear
regions of the galaxies in our sample is presented. We have constructed
smooth models of the old stellar population by fitting elliptical
isophotes to the J- and K-band images. The model-divided images are
examined for the presence of isophotal deviations from elliptical
symmetry, such as internal bars, spiral arms, etc., and compared with
the structures seen in optical emission-line images, to study the
relative orientations of bars, the EELRs, the nuclear radio emission,
and the host galaxy. We find stellar bars in NGC 1068 and NGC 4253 whose
orientations are consistent with those of their EELRs and evidence for
double bars (or "bars within bars") in Mrk 573, NGC 3081, and NGC 3393.
Only in NGC 2110 and NGC 4151 do we find no significant isophotal
deviations from elliptical symmetry. Finally, there is an alignment on
small scales between the near-IR continuum and the line emission in four
galaxies, NGC 1068, NGC 2110, NGC 3081, and NGC 4253. These results seem
to suggest that there is not a unique explanation for the orientation of
the EELRs seen in Seyfert galaxies. In some cases, the EELRs could
represent gas aligned with the nuclear stellar bars, whereas in others,
they are more likely to be related to gas escaping along the minor axis
of the galaxies.
| Title: |
| Total magnitude, radius, colour indices, colour gradients and photometric type of galaxies |
| Authors: |
| PRUGNIEL, PH.; HERAUDEAU, PH. |
| Affiliation: |
| Centre de Recherches Astronomique de Lyon, CNRS, Observatoire de Lyon, F-69561 St-Genis-Laval Cedex, France |
| Journal: |
| Astronomy and Astrophysics Supplement, v.128, p.299-308 |
| Publication Date: |
| 03/1998 |
| Origin: |
| A&AS |
| A&A Keywords: |
| GALAXIES: FUNDAMENTAL PARAMETERS, GALAXIES: GENERAL, GALAXIES: PHOTOMETRY |
| Abstract Copyright: |
| (c) 1998: The European Southern Observatory (ESO) |
| Bibliographic Code: |
| 1998A&AS..128..299P |
Abstract
We present a catalogue of aperture photometry of galaxies, in UBVRI,
assembled from three different origins: (i) an update of the catalogue
of Buta et al. (1995) (ii) published photometric profiles and (iii)
aperture photometry performed on CCD images.
We explored different sets of growth curves to fit these data: (i) The
Sersic law, (ii) The net of growth curves used for the preparation of
the RC3 and (iii) A linear interpolation between the de Vaucouleurs
(r(1/4) ) and exponential laws. Finally we adopted the latter solution.
Fitting these growth curves, we derive (1) the total magnitude, (2) the
effective radius, (3) the colour indices and (4) gradients and (5) the
photometric type of 5169 galaxies. The photometric type is defined to
statistically match the revised morphologic type and parametrizes the
shape of the growth curve. It is coded from -9, for very concentrated
galaxies, to +10, for diffuse galaxies.
Based in part on observations collected at the Haute-Provence
Observatory.
| Title: |
| Starburst Galaxies. III. Properties of a Radio-selected Sample |
| Authors: |
| SMITH, DENISE A.; HERTER, TERRY; HAYNES, MARTHA P. |
| Journal: |
| Astrophysical Journal v.494, p.150 |
| Publication Date: |
| 02/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: INTERACTIONS, GALAXIES: STARBURST, INFRARED: GALAXIES |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...494..150S |
Abstract
We have analyzed the properties of the 20 most radio-luminous UGC
starburst galaxies from Condon, Frayer, & Broderick. Near-infrared
images, spectra, and optical rotation curves were presented in Smith et
al. In this paper, we use these data and published radio data to assess
the stellar populations, dust contents, ionizing conditions, and
dynamics of the starbursts. Certain properties of the star formation
occurring in these galaxies differ from those observed locally. The
infrared excesses (IREs) are lower than and span a narrower range of
values than those of Galactic H II regions. The starbursts appear to
produce a higher proportion of ionizing photons than most Galactic H II
regions. Consequently, the initial mass functions (IMFs) of the
starbursts may be more strongly biased toward high-mass star formation.
The starbursts may also contain fewer old H II regions than the Milky
Way. Furthermore, the starburst IRE is likely to be influenced by the
presence of large reservoirs of gas that absorb a larger fraction of the
Lyman continuum photons. The OB stellar and far-infrared luminosities
imply that the upper mass range of the starburst IMF (M > 10 M&sun;) is
characterized by a slope of 2.7 +/- 0.2. The starburst IMF thus bears a
strong similarity to that observed in Magellanic OB associations.
Optical line ratios indicate that a range of excitation conditions are
present. We conclude that the near-infrared light from many of the
starbursts is dominated by a heavily obscured mixture of emission from
evolved red stars and young blue stars with small contributions (~5%)
from thermal gas and hot dust, under the assumptions that a Galactic or
SMC extinction law can be applied to these systems and that the true
reddening curve follows one of the models currently existing in the
literature. In some cases, larger amounts of emission from blue stars or
hot dust may be required to explain the observed near-infrared colors.
The amount of dust emission exceeds that predicted from comparisons with
Galactic H II regions. The near-infrared colors of some of the systems
may also be influenced by the presence of a low-luminosity active
galactic nucleus (AGN). Emission from blue stars and hot dust, if
present, dilutes the observed CO index. The activity in the redder, more
luminous systems is strongly peaked. The galaxies hosting the starbursts
exhibit a wide range of morphological and star-forming properties. While
all of the host galaxies are interacting systems, the nuclear
separations of the interacting nuclei range from <1 kpc to >1 Mpc. The
dynamical behavior ranges from relaxed to strongly perturbed. The
off-nuclear regions of the galaxies are sites of active star formation
and are characterized by a range of excitation conditions. Spatially
extended LINER emission is consistent with shock excitation produced by
superwinds or galaxy-galaxy collisions. Violent star formation activity
occurs over a larger physical scale in the most active starbursts.
Systems containing mergers and widely separated nuclei possess similar
colors and luminosities. The burst properties are most likely regulated
by the internal structures of the interacting galaxies and not the
separations of the interacting galaxies.
| Title: |
| A statistical study of the spectra of very luminous IRAS galaxies. I. Data |
| Authors: |
| WU, H.; ZOU, Z. L.; XIA, X. Y.; DENG, Z. G. |
| Affiliation: |
| AA(Beijing Astronomical Observatory, Chinese Academy of Sciences, Beijing 100080, China), AB(Beijing Astronomical Observatory, Chinese Academy of Sciences, Beijing 100080, China), AC(Department of Physics, Tianjin Normal University, Tianjin 300074, China; Beijing Astronomical Observatory, Chinese Academy of Sciences, Beijing 100080, China), AD(Department of Physics, Chinese Academy of Sciences Graduate School, Beijing 100039, China; Beijing Astronomical Observatory, Chinese Academy of Sciences, Beijing 100080, China) |
| Journal: |
| Astronomy and Astrophysics Supplement, v.127, p.521-526 |
| Publication Date: |
| 02/1998 |
| Origin: |
| A&AS |
| A&A Keywords: |
| GALAXIES: GENERAL, INFRARED: GALAXIES, GALAXIES: REDSHIFTS, GALAXIES: STATISTICS |
| Abstract Copyright: |
| The European Southern Observatory (ESO) |
| Bibliographic Code: |
| 1998A&AS..127..521W |
Abstract
This paper presents the results of spectral observations for the
largest complete sample of very luminous IRAS galaxies obtained to date.
The sample consists of those 73 objects for which log(L_IR/L_{sun}) >=
11.5
(H_{0}=50;km; s(-1) Mpc(-1) , q_{0}=0.5) and mag <= 15.5 , and was
extracted from the 2 Jy IRAS redshift catalog. All the spectra were
obtained using the 2.16 m telescope of Beijing Astronomical Observatory
during the years 1994-1996. A total of 123 galaxy spectra were obtained
with spectral ranges of 4400;Angstroms to 7100;Angstroms and
3500;Angstroms to 8100;Angstroms at resolutions of 11.2;Angstroms and
9.3;Angstroms respectively. In addition to the 73 spectra for sample
galaxies, we also present spectra for ten non-sample galaxies and a
further 40 for the companions of sample galaxies. The data presented
include nuclear spectrum and the parameters describing the emission
lines, absorption lines and continua as well as DSS images and
environmental parameters.
Table 1 is also available in electric form, Table 2-4 are only available
in electronic form form at the CDS via anonymous ftp to
cdsarc.u-strasbg.fr (130. 79.128.5) or via http:
cdsweb.u-strasbg.fr/Abstract.html. Figures 4 and 9 are published in the
on-line version of A&A..
| Title: |
| X-ray absorption in the strong Feii narrow-line Seyfert 1 galaxy Markarian507 |
| Authors: |
| IWASAWA, K.; BRANDT, W. N.; FABIAN, A. C. |
| Affiliation: |
| AA(Institute of Astronomy, Madingley Road, Cambridge CB3 0HA), AB(Institute of Astronomy, Madingley Road, Cambridge CB3 0HA), AC(Institute of Astronomy, Madingley Road, Cambridge CB3 0HA) |
| Journal: |
| Monthly Notices of the Royal Astronomical Society, Volume 293, Issue 3, pp. 251-256. |
| Publication Date: |
| 01/1998 |
| Origin: |
| MNRAS |
| MNRAS Keywords: |
| GALAXIES: ACTIVE, GALAXIES: INDIVIDUAL: MRK 507, X-RAYS: GALAXIES |
| Abstract Copyright: |
| (c) 1998 The Royal Astronomical Society |
| Bibliographic Code: |
| 1998MNRAS.293..251I |
Abstract
We present results from spectral analysis of ASCA data on the strong
Feii narrow-line Seyfert 1 galaxy Mrk507. This galaxy was found to have
an exceptionally flat ROSAT spectrum among the narrow-line Seyfert 1
galaxies (NLS1s) studied by Boller, Brandt & Fink. The ASCA spectrum,
however, shows a clear absorption feature in the energy band below 2
keV, which partly accounts for the flat spectrum observed with the ROSAT
Position Sensitive Proportional Counter (PSPC). Such absorption is
rarely observed in other NLS1s. The absorption is mainly the result of
cold (neutral or slightly ionized) gas with a column density of
(2-3)x10^21 cm^-2. A reanalysis of the PSPC data shows that an
extrapolation of the best-fitting model for the ASCA spectrum
underpredicts the X-ray emission observed with the PSPC below 0.4 keV if
the absorber is neutral (which indicates that the absorber is slightly
ionized), covers only part of the central source, or there is extra soft
thermal emission from an extended region. There is also evidence that
the X-ray absorption is complex; an additional edge feature marginally
detected at 0.84 keV suggests the presence of an additional
high-ionization absorber, which imposes a strong Oviii edge on the
spectrum. After correction for the absorption, the photon index of the
intrinsic continuum, Gamma~=1.8, obtained from the ASCA data is quite
similar to that of ordinary Seyfert 1 galaxies. Mrk507 still has one of
the flattest continuum slopes among the NLS1s, but is no longer
exceptional. The strong optical Feii emission remains unusual in the
light of the correlation between Feii strengths and steepness of soft
X-ray slope.
| Title: |
| Symmetric Parsec-scale OH Megamaser Structures in Arp 220 |
| Authors: |
| LONSDALE, COLIN J.; LONSDALE, CAROL J.; DIAMOND, PHILIP J.; SMITH, HARDING E. |
| Journal: |
| Astrophysical Journal Letters v.493, p.L13 |
| Publication Date: |
| 01/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, INFRARED: GALAXIES, RADIO LINES: GALAXIES, MASERS |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...493L..13L |
Abstract
The parsec-scale OH megamaser emission in the luminous IR galaxy Arp 220
has been imaged in detail using a global VLBI array. Four major emission
regions are revealed in the 1667 MHz line, each with complex spatial and
velocity structure showing intriguing symmetries. These emission regions
have no associated continuum emission to stringent limits, and the
brighter components have a maser amplification ratio exceeding 800. No
compact emission is detected in the 1665 MHz line. The compact maser
emission, with high amplification and unmeasurably small 1665/1667 line
ratio, appears to be the result of saturated masers in physically
compact masing clouds. The diffuse emission, on the other hand, appears
to fit the traditional OH megamaser model of a low-gain masing screen on
scales of hundreds of parsecs. Infrared pumping is indicated for the
diffuse emission, but collisional pumping is probably important for the
compact components. The compact components may trace shock fronts in the
dense nuclear environment and may be related to active galactic nucleus
activity.
| Title: |
| Physical Conditions of the Molecular Gas in Seyfert Galaxies |
| Authors: |
| PAPADOPOULOS, PADELI P.; SEAQUIST, E. R. |
| Journal: |
| Astrophysical Journal v.492, p.521 |
| Publication Date: |
| 01/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ISM, GALAXIES: SEYFERT, GALAXIES: STARBURST, RADIO LINES: GALAXIES |
| Bibliographic Code: |
| 1998ApJ...492..521P |
Abstract
Not Available
| Title: |
| HST/WFPC2 Observations of Warm Ultraluminous Infrared Galaxies |
| Authors: |
| SURACE, JASON A.; SANDERS, D. B.; VACCA, WILLIAM D.; VEILLEUX, SYLVAIN; MAZZARELLA, J. M. |
| Journal: |
| Astrophysical Journal v.492, p.116 |
| Publication Date: |
| 01/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: INTERACTIONS, GALAXIES: STAR CLUSTERS, GALAXIES: STARBURST, INFRARED: GALAXIES |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...492..116S |
Abstract
We present new high-resolution B- and I-band images of a nearly complete
sample of nine "warm" (f25/f60 > 0.2), ultraluminous infrared galaxies
(ULIGs) obtained with the Wide Field Planetary Camera of the Hubble
Space Telescope (HST). The HST images clearly reveal the presence of
tidal tails and other features associated with merging galaxies. All of
the warm ULIGs show evidence of complex structures such as dust lanes
and spiral features in their inner few kiloparsecs. Additionally, they
show compact, blue "knots" of star formation (between 4 and 31 knots per
object) that appear similar to those seen in more nearby merger systems.
Spectral synthesis modeling is used to estimate mean upper age limits
and masses: the median upper age limit for the knots in individual
galaxies is ~3 x 108 yr (ranging from ~107 to 1 x 109 yr), and the range
of knot masses is ~105-109 M&sun;. We also argue that these starburst
knots cannot be significant contributors to the extremely high
bolometric luminosity of these galaxies. Additionally, each object
contains one or two knots whose luminosity and color are implausible in
terms of star formation; we identify these as putative active nuclei.
These observations are consistent with the hypothesis that warm ULIGs
may represent a critical transition stage in the evolution of ULIGs into
optical quasi-stellar objects.
| Title: |
| Detection of CO (3--2) Emission at z = 2.64 from the Gravitationally Lensed Quasar MG 0414+0534 |
| Authors: |
| BARVAINIS, RICHARD; ALLOIN, DANIELLE; GUILLOTEAU, STEPHANE; ANTONUCCI, ROBERT |
| Journal: |
| Astrophysical Journal Letters v.492, p.L13 |
| Publication Date: |
| 01/1998 |
| Origin: |
| APJ |
| ApJ Keywords: |
| TECHNIQUES: MISCELLANEOUS, RADIO CONTINUUM: GENERAL |
| Abstract Copyright: |
| (c) 1998: The American Astronomical Society |
| Bibliographic Code: |
| 1998ApJ...492L..13B |
Abstract
We have detected CO (3-2) line emission from the gravitationally lensed
quasar MG 0414+0534 at redshift 2.64, using the IRAM Plateau de Bure
Interferometer. The line is broad, with Delta v_{{FWHM}}=580 km s ^{-1}
. The velocity-integrated CO flux is comparable to, but somewhat smaller
than, that of IRAS F10214+4724 and the Cloverleaf quasar (H1413+117),
both of which are at similar redshifts. The lensed components A1 + A2
and B were resolved, and separate spectra are presented for each. We
also observed the unlensed radio-quiet quasar PG 1634+706 at z=1.33 ,
finding no significant CO emission.
| Title: |
| A catalogue of spatially resolved kinematics of galaxies: Bibliography |
| Authors: |
| PRUGNIEL, PH.; ZASOV, A.; BUSARELLO, G.; SIMIEN, F. |
| Affiliation: |
| AA(CRAL-Observatoire de Lyon, CNRS: UMR 142, F-69561 St-Genis-Laval Cedex, France), AB(Sternberg Astronomical Institute, Universitetskij prospect, 119899, Moscow, Russia), AC(Osservatorio Astronomico di Capodimonte, via Moiariello 16, I-80131 Napoli, Italy), AD(CRAL-Observatoire de Lyon, CNRS: UMR 142, F-69561 St-Genis-Laval Cedex, France) |
| Journal: |
| Astronomy and Astrophysics Supplement, v.127, p.117-118 |
| Publication Date: |
| 01/1998 |
| Origin: |
| A&AS |
| A&A Keywords: |
| CATALOGS, GALAXIES GENERAL, GALAXIES: KINEMATICS AND DYNAMICS |
| Abstract Copyright: |
| The European Southern Observatory (ESO) |
| Bibliographic Code: |
| 1998A&AS..127..117P |
Abstract
We present a catalogue of galaxies for which spatially resolved data on
their internal kinematics have been published; there is no a priori
restriction regarding their morphological type. The catalogue lists the
references to the articles where the data are published, as well as a
coded description of these data: observed emission or absorption lines,
velocity or velocity dispersion, radial profile or 2D field, position
angle.
Tables 1, 2, and 3 are proposed in electronic form only, and are
available from the CDS, via anonymous ftp to cdsarc.u-strasbg.fr (to
130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html
| Title: |
| The Deep Silicate Absorption Feature in IRAS 08572+3915 and Other Infrared Galaxies |
| Authors: |
| DUDLEY, C. C.; WYNN-WILLIAMS, C. G. |
| Journal: |
| Astrophysical Journal v.488, p.720 |
| Publication Date: |
| 10/1997 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: INDIVIDUAL NAME: ARP 220, GALAXIES: INDIVIDUAL ALPHANUMERIC: IRAS 08572+3915, GALAXIES: INDIVIDUAL NGC NUMBER: NGC 4418, GALAXIES: ISM, GALAXIES: NUCLEI, INFRARED: GALAXIES |
| Abstract Copyright: |
| (c) 1997: The American Astronomical Society |
| Bibliographic Code: |
| 1997ApJ...488..720D |
Abstract
New mid-infrared (10 and 20 mu m) spectrophotometry of the ultraluminous
infrared galaxy IRAS 08572+3915 is presented. The 10 mu m spectrum
reveals a deep silicate absorption feature, while the 20 mu m spectrum
shows no clear evidence for an 18 mu m silicate absorption feature. An
interstellar extinction curve is fitted to IRAS 08572+3915 and two other
deep silicate infrared galaxies, NGC 4418 and Arp 220. It is found that
pure extinction cannot explain the spectral energy distributions of
these sources. On the other hand, both the strength of the silicate
absorption and the overall spectral energy distributions of the three
galaxies agree well with scaled-up models of galactic protostars. From
this agreement, we conclude that the infrared emission comes from an
optically thick dust shell surrounding a compact power source. The size
of the power source is constrained to be smaller than a few parsecs. We
argue that a significant portion of the total luminosities of these
galaxies arises from an active galactic nucleus deeply embedded in
dust.
| Title: |
| Redshifts for flat-spectrum radio sources in the second Caltech-Jodrell Bank VLBI sample |
| Authors: |
| HENSTOCK, D. R.; BROWNE, I. W. A.; WILKINSON, P. N.; MCMAHON, R. G. |
| Affiliation: |
| AA(University of Manchester, Nuffield Radio Astronomy Laboratories, Jodrell Bank, Macclesfield, Cheshire SK11 9DL), AB(University of Manchester, Nuffield Radio Astronomy Laboratories, Jodrell Bank, Macclesfield, Cheshire SK11 9DL), AC(University of Manchester, Nuffield Radio Astronomy Laboratories, Jodrell Bank, Macclesfield, Cheshire SK11 9DL), AD(Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA) |
| Journal: |
| Monthly Notices of the Royal Astronomical Society, Volume 290, Issue 2, pp. 380-400. |
| Publication Date: |
| 09/1997 |
| Origin: |
| MNRAS |
| MNRAS Keywords: |
| BL LACERTAE OBJECTS: GENERAL, GALAXIES: DISTANCES AND REDSHIFTS, GALAXIES: GENERAL, QUASARS: EMISSION LINES, QUASARS: GENERAL, RADIO CONTINUUM: GENERAL |
| Abstract Copyright: |
| (c) 1997 The Royal Astronomical Society |
| Bibliographic Code: |
| 1997MNRAS.290..380H |
Abstract
We present optical spectra and redshifts for flat-spectrum radio sources
taken from the second Caltech-Jodrell Bank VLBI sample. The sources were
observed using the Faint Object Spectrograph on the Isaac Newton
Telescope. We show optical spectra for 90 sources, out of a total of 101
observed; of the remaining 11 sources, nine were not detected, and two
were mis-identified. Definite redshifts have been determined for 60
sources, and a further seven have probable redshifts determined. Five
sources are shown to have featureless BL Lac type spectra, and 18
sources are too weak to give a reliable redshift.
| Title: |
| Optical and Far-Infrared Emission of IRAS Seyfert Galaxies |
| Authors: |
| BONATTO, CHARLES J.; PASTORIZA, MIRIANI G. |
| Journal: |
| Astrophysical Journal v.486, p.132 |
| Publication Date: |
| 09/1997 |
| Origin: |
| APJ |
| ApJ Keywords: |
| ISM: DUST, EXTINCTION, GALAXIES: PHOTOMETRY, GALAXIES: SEYFERT, INFRARED: GALAXIES |
| Abstract Copyright: |
| (c) 1997: The American Astronomical Society |
| Bibliographic Code: |
| 1997ApJ...486..132B |
Abstract
This paper presents an analysis of moderately large samples of type 1
and 2 Seyfert galaxies through optical observations and far-infrared
IRAS data, also taking into account theoretical color indices derived
from dust emission models. The galaxies in the samples cover a rather
large interval in far-infrared luminosity, i.e., 7.6 <= log (LIR/L&sun;)
<= 12.6. We show that both types of Seyferts have approximately the same
distribution of number of objects with a given LIR. Galaxies with
similar far-infrared color indices alpha (100, 60) are grouped together,
and the corresponding average color indices are interpreted in terms of
a simple model in which the observed colors result from the combination
of dust directly heated by the active galactic nucleus with a component
from the host galaxy represented by the emission of cool dust. On the
basis of the average IRAS colors of the derived groups, we show that
type 1 and 2 Seyfert galaxies are undistinguishable from each other.
From the luminosity ratios LIR/LH alpha and LIR/L[O III], we show that
basically the same model can be applied to both types of Seyfert, only
allowing for the variation of model conditions: type 2 Seyferts would be
like type 1 Seyferts but with the Seyfert nucleus and broad line region
more effectively "hidden" by dust.
| Title: |
| The Infrared Bright Nuclei in the Mid-Infrared |
| Authors: |
| KETO, ERIC; HORA, JOSEPH L.; DEUTSCH, LYNNE; HOFFMANN, WILLIAM; FAZIO, G. G.; BALL, ROGER; MEIXNER, MARGARET; SKINNER, CHRISTOPHER; ARENS, J. F.; JERNIGAN, GARRETT |
| Journal: |
| Astrophysical Journal v.485, p.598 |
| Publication Date: |
| 08/1997 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: INDIVIDUAL NGC NUMBER: NGC 6240, GALAXIES: INDIVIDUAL ALPHANUMERIC: IRAS 0518-25, GALAXIES: INDIVIDUAL NAME: ARP 299, GALAXIES: NUCLEI, GALAXIES: STARBURST, INFRARED: GALAXIES |
| Abstract Copyright: |
| (c) 1997: The American Astronomical Society |
| Bibliographic Code: |
| 1997ApJ...485..598K |
Abstract
We present arcsecond angular-resolution mid-IR images of three IR-bright
galaxies, NGC 6240, IRAS 0518-25, and the NGC 3690--IC 694 (Arp 299)
system, and we compare the sizes of their emission regions in the mid-IR
and near-IR. In all these galaxies, most (~75%) of the mid-IR flux, as
measured in the IRAS 12 mu m observations, is found in our images to be
concentrated within the central few hundred parsecs. In the two galaxies
which show a single IR source in the nucleus, IRAS 0518-25 and IC 694,
the mid-IR emission is more compact than the near-IR. This suggests that
the mid-IR source, warm dust heated by an active galactic nucleus or an
unresolved starburst, is more compact than the population of cooler,
older stars. In the two galaxies which show double sources in the
nucleus, the reverse is the case. That is, the mid-IR is more extended
than the near-IR. Similar results are obtained for a handful of other
galaxies for which we have high-resolution mid-IR data. Thus in our
small sample, the double source nuclei contain starbursts which are more
extended than the older stars and the single source nuclei do not. Some
of the double sources seen in the IR bright galaxies, for example NGC
3690, are probably starbursts in conjunction with a galactic nucleus
rather than twin galactic nuclei.
| Title: |
| Molecular Gas, Morphology, and Seyfert Galaxy Activity |
| Authors: |
| MAIOLINO, R.; RUIZ, M.; RIEKE, G. H.; PAPADOPOULOS, P. |
| Journal: |
| Astrophysical Journal v.485, p.552 |
| Publication Date: |
| 08/1997 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: ISM, GALAXIES: SEYFERT, GALAXIES: STRUCTURE |
| Abstract Copyright: |
| (c) 1997: The American Astronomical Society |
| Bibliographic Code: |
| 1997ApJ...485..552M |
Abstract
We probe the cause of the elevated star formation in host galaxies of
Seyfert 2 nuclei compared with Seyfert 1 hosts and with field galaxies.
12CO (1--0) observations of a large sample of Seyfert galaxies indicate
no significant difference in the total amount of molecular gas as a
function of the Seyfert nuclear type, nor are Seyfert galaxies
significantly different in this regard from a sample of field galaxies
once selection effects are accounted for. Therefore, the total amount of
molecular gas is not responsible for the enhanced star-forming activity
in Seyfert 2 hosts. To probe how this gas is being converted more
efficiently into stars in Seyfert 2 hosts than in the other galaxies, we
investigate the occurrence of bars, interactions, and distorted
morphologies among Seyfert galaxies. We find a significantly higher rate
of asymmetric morphologies for Seyfert 2 galaxies with respect to
Seyfert 1 galaxies and field galaxies. Relative to field galaxies, the
effect is at a greater than 99.9% confidence level. The presence of
asymmetric morphologies in individual Seyfert galaxies is correlated
with their tendency to exhibit enhanced star-forming activity. These
results suggest that asymmetric morphologies are an important cause for
the link between Seyfert type and star-forming activity: bars and
distortions in Seyfert 2 hosts are likely both to enhance star-forming
activity and to funnel gas into the nuclear region, thus obscuring and
possibly contributing to the feeding of the active nucleus.
| Title: |
| The Average Properties of the Dense Molecular Gas in Galaxies |
| Authors: |
| PAGLIONE, TIMOTHY A. D.; JACKSON, JAMES M.; ISHIZUKI, SUMIO |
| Journal: |
| Astrophysical Journal v.484, p.656 |
| Publication Date: |
| 07/1997 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ISM, GALAXIES: STARBURST, GALAXIES: STELLAR CONTENT, RADIO LINES: GALAXIES |
| Abstract Copyright: |
| (c) 1997: The American Astronomical Society |
| Bibliographic Code: |
| 1997ApJ...484..656P |
Abstract
We have observed the HCN J = 3 --> 2 and J = 1 --> 0 emission from
several nearby starburst and normal galaxies. These lines have large
critical densities ( n_{{H}_{2}} > 106 cm-3) and excitation energies (Eu
> 25 K). Thus, they probe the warm and dense molecular gas where massive
stars typically form. The average cloud densities of these galaxies, as
estimated from the ratio of the HCN J = 3 --> 2 and 1 --> 0 integrated
intensities, is correlated with their star formation efficiency.
Therefore, the average densities of the molecular clouds in starburst
nuclei are higher than those of more quiescent galaxies. Further, the
starburst galaxies NGC 253 and M82 have a much higher fraction of
molecular mass at high density ( n_{{H}_{2}} > 104 cm-3) than the normal
galaxies IC 342 and the Milky Way. These results imply that the clouds
in starburst nuclei form stars more efficiently than those in normal
galaxies.
| Title: |
| On the polarization of resonantly scattered emission lines - III. Polarization of quasar broad emission lines and broad absorption line troughs |
| Authors: |
| LEE, H.-W.; BLANDFORD, R. D. |
| Affiliation: |
| AA( Department of Theoretical Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA ), AB( Department of Theoretical Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA ) |
| Journal: |
| Monthly Notices of the Royal Astronomical Society, Volume 288, Issue 1, pp. 19-24. |
| Publication Date: |
| 06/1997 |
| Origin: |
| MNRAS |
| MNRAS Keywords: |
| POLARIZATION, GALAXIES: KINEMATICS AND DYNAMICS, QUASARS: ABSORPTION LINES, QUASARS: EMISSION LINES |
| Abstract Copyright: |
| (c) 1997 The Royal Astronomical Society |
| Bibliographic Code: |
| 1997MNRAS.288...19L |
Abstract
The contribution to the expected linear polarization of quasar broad
emission and absorption lines from resonance scattering is computed
using a Monte Carlo approach for specific, generic models. Attention is
focused on the external illumination of the scattering region. The
polarization of the reflected component from an externally illuminated
slab with finite optical depth is first considered as a model of a
single, dense, broad emission-line cloud. A polarization <~40 per cent
(<~10 per cent) is typically computed for J=0-->1 (J=1/2-->3/2)
transitions. Integration over a population of emission-line clouds
typically reduces the observed polarization by a factor
~(0.1-0.3)q_BELR, where q_BELR is the covering factor for emission
lines, while preserving the relative polarizations of different lines.
Consequently, the low degree of polarization observed in the red wings
of quasar emission lines limits the density of low column density
emission- line clouds. Broad absorption lines are associated with
outflowing gas of lower density. The polarization of both the
transmitted and the reflected radiation is next computed for simple
kinematic models of the outflow and the observed integrated polarization
in the absorption-line troughs is found to be typically ~10 per cent. An
equatorial flow model gives a large degree of polarization (~0.15)
parallel to the symmetry axis in the absorption trough for the doublet
transition J=1/2-->1/2, 3/2, and the polarized flux is found to extend
to the red side. In contrast, we obtain a smaller degree of polarization
(~0.05) perpendicular to the jet axis from a bipolar flow model and the
polarized flux is concentrated to the blue side of the line profile. It
is predicted that the troughs of singlet J=0-->1 lines, such as C iii
lambda977, should exhibit larger degrees of polarization if this is due
to resonance scattering. Polarization observations of quasar emission
lines promise to be a powerful diagnostic of the kinematics of gas in
the central pc of a quasar.
| Title: |
| A Survey for H 2O Megamasers in Active Galactic Nuclei. II. A Comparison of Detected and Undetected Galaxies |
| Authors: |
| BRAATZ, J. A.; WILSON, A. S.; HENKEL, C. |
| Journal: |
| Astrophysical Journal Supplement v.110, p.321 |
| Publication Date: |
| 06/1997 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: NUCLEI, GALAXIES: SEYFERT, ISM: MOLECULES, MASERS, RADIO LINES: GALAXIES |
| Abstract Copyright: |
| (c) 1997: The American Astronomical Society |
| Bibliographic Code: |
| 1997ApJS..110..321B |
Abstract
A survey for H2O megamaser emission from 354 active galaxies has
resulted in the detection of 10 new sources, making 16 known altogether.
The galaxies surveyed include a distance-limited sample (covering
Seyferts and LINERs with recession velocities less than 7000 km s-1) and
a magnitude-limited sample (covering Seyferts and LINERs with mB <=
14.5). In order to determine whether the H2O-detected galaxies are
"typical" active galactic nuclei (AGNs) or have special properties that
facilitate the production of powerful masers, we have accumulated a
database of physical, morphological, and spectroscopic properties of the
observed galaxies. The most significant finding is that H2O megamasers
are detected only in Seyfert 2 and LINER galaxies, not Seyfert 1's. This
lack of detection in Seyfert 1's indicates either that they do not have
molecular gas in their nuclei with physical conditions appropriate to
produce 1.3 cm H2O masers or that the masers are beamed away from Earth,
presumably in the plane of the putative molecular torus that hides the
Seyfert 1 nucleus in Seyfert 2's. LINERs are detected at a similar rate
to Seyfert 2's, which constitutes a strong argument that at least some
nuclear LINERs are AGNs rather than starbursts, since starbursts have
not been detected as H2O megamasers. We preferentially detect H2O
emission from the nearer galaxies and from those that are apparently
brighter at mid- and far-infrared and centimeter radio wavelengths.
There is also a possible trend for the H2O-detected galaxies to be more
intrinsically luminous in nuclear 6 cm radio emission than the
undetected ones, though these data are incomplete. We find evidence that
Seyfert 2's with very high (NH > 1024 cm-2) X-ray--absorbing columns of
gas are more often detected as H2O maser emitters than Seyfert 2's with
lower columns. It may be that the probability of detecting H2O maser
emission in Seyfert galaxies increases with increasing column of cool
gas to the nucleus, from Seyfert 1's through narrow-line X-ray galaxies
to Seyfert 2's.
| Title: |
| THE ROLE OF STARBURSTS IN LUMINOUS INFRARED GALAXIES |
| Authors: |
| COLINA, L.; PEREZ-OLEA, D. PLANESAS, P. |
| Journal: |
| Revista Mexicana de Astronomia y Astrofisica Serie de Conferencias, Vol. 6, 1st Guillermo Haro Conference on Astrophysics: Starburst Activity in Galaxies, Puebla, Pue., Mexico, April 29-May 3, 1996, p. 84. |
| Publication Date: |
| 05/1997 |
| Origin: |
| RMxAA |
| Bibliographic Code: |
| 1997RMxAC...6...84C |
Abstract
Not Available
| Title: |
| EXTRAGALACTIC SPECTROSCOPY WITH THE INFRARED SPACE OBSERVATORY |
| Authors: |
| GENZEL, R.; LUTZ, D.; EGAMI, E.; KUNZE, D.; RIGOPOULOU, D.; STURM, E.; MOORWOOD, A. F. M.; DEGRAAUW, TH.; STERNBERG, A. |
| Journal: |
| Revista Mexicana de Astronomia y Astrofisica Serie de Conferencias, Vol. 6, 1st Guillermo Haro Conference on Astrophysics: Starburst Activity in Galaxies, Puebla, Pue., Mexico, April 29-May 3, 1996, p. 70. |
| Publication Date: |
| 05/1997 |
| Origin: |
| RMxAA |
| Bibliographic Code: |
| 1997RMxAC...6...70G |
Abstract
Not Available
| Title: |
| LUMINOUS INFRARED GALAXIES |
| Authors: |
| SANDERS, D. B. |
| Journal: |
| Revista Mexicana de Astronomia y Astrofisica Serie de Conferencias, Vol. 6, 1st Guillermo Haro Conference on Astrophysics: Starburst Activity in Galaxies, Puebla, Pue., Mexico, April 29-May 3, 1996, p. 42. |
| Publication Date: |
| 05/1997 |
| Origin: |
| RMxAA |
| Bibliographic Code: |
| 1997RMxAC...6...42S |
Abstract
Not Available
| Title: |
| Spectropolarimetry of High-Polarization Seyfert I Galaxies |
| Authors: |
| MARTEL, ANDRE R. |
| Journal: |
| Publications of the Astronomical Society of the Pacific, v.109, p.630 |
| Publication Date: |
| 05/1997 |
| Origin: |
| PASP |
| Abstract Copyright: |
| (c) 1997: Astronomical Society of the Pacific |
| Bibliographic Code: |
| 1997PASP..109..630M |
Abstract
Not Available.
(SECTION: Dissertation Summaries)
| Title: |
| Spectroscopy of Close Companions to Quasi-Stellar Objects and the Ages of Interaction-Induced Starbursts |
| Authors: |
| CANALIZO, GABRIELA; STOCKTON, ALAN |
| Journal: |
| Astrophysical Journal Letters v.480, p.L5 |
| Publication Date: |
| 05/1997 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: EVOLUTION, GALAXIES: INTERACTIONS, GALAXIES: QUASARS: INDIVIDUAL ALPHANUMERIC: 3C 323.1, GALAXIES: QUASARS: INDIVIDUAL ALPHANUMERIC: PG 1700+518, GALAXIES: QUASARS: INDIVIDUAL ALPHANUMERIC: PKS 2135-147 |
| Abstract Copyright: |
| (c) 1997: The American Astronomical Society |
| Bibliographic Code: |
| 1997ApJ...480L...5C |
Abstract
We present low-resolution absorption-line spectra of three candidate
close (<3") companions to the low-redshift QSOs 3CR 323.1, PG 1700+518,
and PKS 2135-147. The spectra were obtained with the Low-Resolution
Imaging Spectrometer (LRIS) on the Keck telescopes and with the Faint
Object Spectrograph on the University of Hawaii 2.2 m telescope. For 3CR
323.1 and PG 1700+518, we measure relative velocities that are
consistent with an association between the QSOs and their companion
galaxies. The spectral features of the companion galaxy to 3CR 323.1
indicate a stellar population of intermediate age (~2.3 Gyr). In
contrast, the spectrum of the companion object to PG 1700+518 shows
strong Balmer absorption lines from a relatively young stellar
population, along with the Mg I b absorption feature and the 4000 A
break from an older population. By modeling the two stellar components
of this spectrum, it is possible to estimate the time that has elapsed
since the end of the most recent major starburst event: we obtain
approximately 0.1 Gyr. This event may have coincided with an interaction
that triggered the QSO activity. Finally, our spectroscopy shows
conclusively that the supposed companion to PKS 2135-147 is actually a
projected Galactic G star.
| Title: |
| The Molecular Interstellar Medium in Ultraluminous Infrared Galaxies |
| Authors: |
| SOLOMON, P. M.; DOWNES, D.; RADFORD, S. J. E.; BARRETT, J. W. |
| Journal: |
| Astrophysical Journal v.478, p.144 |
| Publication Date: |
| 03/1997 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ISM, GALAXIES: NUCLEI, GALAXIES: STARBURST, INFRARED: GALAXIES, RADIO LINES: GALAXIES |
| Abstract Copyright: |
| (c) 1997: The American Astronomical Society |
| Bibliographic Code: |
| 1997ApJ...478..144S |
Abstract
We present observations with the IRAM 30 m telescope of CO in a large
sample of ultraluminous IR galaxies out to redshift z = 0.3. Most of the
ultraluminous galaxies in this sample are interacting, but not
completed, mergers. The CO(1--0) luminosity of all but one of the
ultraluminous galaxies is high, with values of log (L^{'}_{{CO}}/{K} km
s-1 pc2 ) = 9.92 +/- 0.12. The extremely small dispersion of only 30% is
less than that of the far-infrared luminosity. The integrated CO line
intensity is strongly correlated with the 100 mu m flux density, as
expected for a blackbody model in which the mid- and far-IR radiation is
optically thick. We use this model to derive sizes of the FIR- and
CO-emitting regions and the enclosed dynamical masses. Both the IR and
CO emission originate in regions a few hundred parsecs in radius. The
median value of L_{{FIR}}/L^{'}_{{CO}}=160 L&sun;/K km s-1 pc2, within a
factor of 2 or 3 of the blackbody limit for the observed far-IR
temperatures. The entire ISM is a scaled-up version of a normal galactic
disk with the ambient densities a factor of 100 higher, making even the
intercloud medium a molecular region. We compare three different
techniques of H2 mass estimation and conclude that the ratio of gas mass
to CO luminosity is about a factor of 4 times lower than for giant
molecular clouds (GMCs) but that the gas mass is a large fraction of the
dynamical mass. Our analysis of CO emission from ultraluminous galaxies
reduces the H2 mass from previous estimates of 2--5 x 1010 M&sun; to
0.4--1.5 x 1010 M&sun;, which is in the range found for molecular
gas-rich spiral galaxies. A collision involving a molecular gas-rich
spiral could lead to an ultraluminous galaxy powered by central
starbursts triggered by the compression of infalling preexisting GMCs.
The extremely dense molecular gas in the center of an ultraluminous
galaxy is an ideal stellar nursery for a huge starburst.
| Title: |
| Spectroscopy of Luminous Infrared Galaxies at 2 Microns. II. Data for Galaxies with 11.2 <= (L IR/L ) 11.9 |
| Authors: |
| GOLDADER, JEFFREY D.; JOSEPH, R. D.; DOYON, RENE; SANDERS, D. B. |
| Journal: |
| Astrophysical Journal Supplement v.108, p.449 |
| Publication Date: |
| 02/1997 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: PHOTOMETRY, GALAXIES: STARBURST, INFRARED: GALAXIES |
| Abstract Copyright: |
| (c) 1997: The American Astronomical Society |
| Bibliographic Code: |
| 1997ApJS..108..449G |
Abstract
Spectra across the infrared K band are presented for a flux-limited
sample of powerful, bright, "infrared" galaxies. The sample in the
present paper, consisting of 43 systems (47 individual galaxies) with
infrared luminosities LIR in the range 11.2 <~ log (LIR/L&sun;) <~ 11.9,
was chosen from the IRAS Bright Galaxy Catalogue. The spectra have
resolving powers of ~340--680. When combined with the 13 spectra we have
already published for the "ultraluminous" galaxies, those with log
(LIR/L&sun;) >~ 12.0, this constitutes the largest database of
high-quality infrared spectra yet assembled for a well-defined sample of
galaxies. The spectra are, in general, dominated by emission lines,
which are due to the Br gamma hydrogen recombination line and to several
quadrupole transitions of excited molecular hydrogen. Emission from He I
also appears frequently. Deep absorption bands from CO are present in
virtually all the spectra, as are a variety of weaker stellar absorption
features. The data are analyzed in a companion paper (Paper III).
| Title: |
| Spectroscopy of Luminous Infrared Galaxies at 2 Microns. III. Analysis for Galaxies with log (L IR/L ) 11.2 |
| Authors: |
| GOLDADER, JEFFREY D.; JOSEPH, R. D.; DOYON, RENE; SANDERS, D. B. |
| Journal: |
| Astrophysical Journal v.474, p.104 |
| Publication Date: |
| 01/1997 |
| Origin: |
| APJ |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: PHOTOMETRY, GALAXIES: STARBURST, INFRARED: GALAXIES |
| Abstract Copyright: |
| (c) 1997: The American Astronomical Society |
| Bibliographic Code: |
| 1997ApJ...474..104G |
Abstract
We have obtained spectra across the K window for the first large sample
of luminous galaxies selected from the IRAS survey. This paper contains
the principal analysis of the 43 systems in our sample with luminosities
of 11.2 <~ log (LIR/L&sun;) <~ 11.9. The spectra themselves were
presented in a companion paper by Goldader et al. (Paper II). The Br
gamma luminosities are proportional to LIR, at levels similar to those
of star-forming regions. This strongly suggests that star formation
accounts for the bulk of the energy production in these objects, in
general agreement with previous studies. Good agreement is found for the
continuous star formation models of Leitherer & Heckman with upper mass
cutoffs well below 100 ℳ_{solar} . The models accommodate a range
in starburst ages of ~107 to 109 yr. Instantaneous starburst models fit
the data but imply an unrealistically short range of ages for the entire
sample. It is difficult to avoid concluding that the initial mass
functions are deficient in stars of less than ~1 ℳ_{solar} . Strong
emission lines from molecular hydrogen are detected. The H2 v = 1--0
S(1) line luminosities are proportional to LIR; the correlation extends
through the ultraluminous infrared galaxies. The H2 emission in the
galaxies tends to be more spatially extended than the Br gamma emission.
Measured values and upper limits for the ratios of the various H2 lines
visible in our spectra indicate that the H2 seen in emission at 2 mu m
is consistent with being shock excited. However, other mechanisms,
operating at sufficiently high densities that the H2 energy levels are
thermalized by collisions, cannot be excluded. Based on energy
considerations, we suggest that the shocks are due to supernova remnants
expanding into the interstellar medium. The frequency of Type II
supernovae necessary to account for the H2 line emission agrees with
frequencies deduced from the starburst models and the radio/far-infrared
correlation. However, there remain a number of galaxies that cannot be
made to fit this model. A decade after its discovery, a universal
explanation of the strong H2 emission in luminous infrared galaxies
continues to elude us. No previously unrecognized broad-line active
nuclei were discovered in our survey; either they are weak or absent or
the true optical depths at 2 mu m are much higher than indicated by
conventional extinction measures. However, there are clear differences
between the K-band properties of galaxies that contain broad-line active
nuclei and those that do not. The differences seem to be due to the
presence of strong nonstellar continuum emission coming from the active
nuclei themselves. With the addition of the 13 ultraluminous galaxies
with log (LIR/L&sun;) >~ 12 from Goldader et al. (Paper I), the number
of systems observed in this program totals 56. We have incorporated
these ultraluminous galaxies in some parts of the analysis to examine
properties across the entire luminosity range of our sample.
| Title: |
| Radio Spectra of Radio Quiet Quasars.II.Broad Absorption Line Quasars |
| Authors: |
| BARVAINIS, RICHARD; LONSDALE, COLIN |
| Journal: |
| Astronomical Journal v.113, p. 144-147 (1997) |
| Publication Date: |
| 01/1997 |
| Origin: |
| AJ |
| Bibliographic Code: |
| 1997AJ....113..144B |
Abstract
Radio continuum spectra are presented for 15 Broad Absorption Line
Quasars (BALQs), obtained with the VLA and typically covering four
frequencies in the observed range 1.5 to 14.9 GHz. We find the
radio spectral shapes of BALQs to be heterogeneous and similar to
the shapes found in a general sample of 39 radio quiet quasars
(which included 8 BALQs) studied in a previous paper (Barvainis,
Lonsdale, & Antonucci 1996). Overall the spectral shapes of radio
quiet quasars, including BALQs, are similar to those of radio loud
quasars.
| Title: |
| Preliminary results on the study of the environment of a complete sample of Seyfert galaxies |
| Authors: |
| SALVATO, M.; RAFANELLI, P. |
| Journal: |
| Memorie della Societa' Astronomica Italiana; 2nd National Meeting on Active Galactic Nuclei, vol.68, no.1, p. 305-308 |
| Publication Date: |
| 00/1997 |
| Origin: |
| AUTHOR |
| Keywords: |
| ACTIVE GALAXIES, SEYFERT GALAXIES |
| Bibliographic Code: |
| 1997MmSAI..68..305S |
Abstract
The results of the study of the environment of a complete sample of
Seyfert galaxies taken from the CfA Redshift Survey are presented. The
distributions of the positions and of the R magnitudes of all galaxies
located within five diameters from the Seyfert galaxies of the sample
are compared with the distributions of the same parameters measured on a
control sample of normal galaxies taken from the MERCG. This research
has been carried out using the images of the "Digitized Sky Survey" and
the on--line catalogues APM and APS.
| Title: |
| Preliminary results on the study of the environment of a complete sample of Seyfert galaxies |
| Authors: |
| SALVATO, M.; RAFANELLI, P. |
| Journal: |
| Astronomische Nachrichten, vol. 318, no. 4, p. 237. |
| Publication Date: |
| 00/1997 |
| Origin: |
| AN |
| Abstract Copyright: |
| (c) 1997: Astronomische Nachrichten |
| Bibliographic Code: |
| 1997AN....318..237S |
Abstract
The results of the study of the environment of a complete sample of
Seyfert galaxies taken from the CfA Redshift Survey (Davis et al. 1983;
Huchra et al. 1983) are shown. In particular we compare the distribution
of the positions of all galaxies located within five diameters from each
Seyfert galaxy of our sample with the analogous distribution observed in
a control sample of normal galaxies taken from the Merged Catalogue of
Galaxies (hereafter MERCG) (Kogoshvili 1986). This research is based on
the analysis of the digitized images of the "Digitized Sky Survey" and
on the on--line catalogues APM (Automatic Plate Measuring System) and
APS (Automated Plate Scanner).
| Title: |
| The Radio Properties of Seyfert Galaxies in the 12 Micron and CfA Samples |
| Authors: |
| RUSH, BRIAN; MALKAN, MATTHEW A.; EDELSON, RICHARD A. |
| Journal: |
| Astrophysical Journal v.473, p.130 |
| Publication Date: |
| 12/1996 |
| Origin: |
| APJ; NED |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: SEYFERT, INFRARED: GALAXIES, RADIO CONTINUUM: GALAXIES, SURVEYS |
| Bibliographic Code: |
| 1996ApJ...473..130R |
Abstract
We report the results of 20, 6, and 2 cm VLA and 1.5 cm OVRO
observations of two similar radio-quiet active galaxy and quasar (AGN)
samples: the optically selected CfA Seyfert galaxies and the bolometric
flux-limited 12 micron active galaxy sample. Every object observed was
detected at 6 cm. Only ~6%-~8% of the 12 micron sample Seyfert galaxies
(three to four objects) are radio-loud (and none of the CfA sample), as
compared to 15%-20% for the Bright Quasar Survey quasars. These radio-
loud objects are compact and have flat spectra, distinguishing them from
the more common radio-quiet objects. The 6-20 cm slopes of the Seyfert
1's and 2's are similar, with average values of <{alpha}^20^_6 cm_> =
-0.66 and -0.71, respectively. Although several Seyfert 1's are
significantly flatter than this in their 6-20 and/or 1.5-6 cm slopes,
there is no systematic trend for either Seyfert type to display upward
or downward spectral curvature. Excluding the radio-loud quasars, the
integrated 6 cm radio luminosity is linearly proportional to the 60
micron luminosity over several orders of magnitude, with on average
twice the radio power of normal spirals of the same far-infrared power.
About half of the objects show extended 6 cm emission, contributing on
average 33% of the total flux. Thus the luminosities of these extended
components alone are comparable to normal spirals of similar infrared
luminosities. The 12 micron sample radio luminosity function is slightly
higher than that of the CfA sample. The integrated space density of
Seyfert 2's is ~2 times that of Seyfert 1's over their common range in
luminosity. In terms of the standard unified model, this ratio in space
density corresponds to a typical half-angle of the torus of {theta} ~
48^deg^.
| Title: |
| A compiled catalogue of optical positions of extragalactic radio sources. |
| Authors: |
| LI, J.; JIN, W. |
| Journal: |
| Astronomy and Astrophysics Supplement, v.120, p.201-205 |
| Publication Date: |
| 12/1996 |
| Origin: |
| A&A via CDS |
| A&A Keywords: |
| ASTROMETRY, REFERENCE FRAMES, CATALOGUES, RADIO CONTINUUM: GALAXIES |
| Abstract Copyright: |
| (c) 1996: Astronomy & Astrophysics |
| Bibliographic Code: |
| 1996A&AS..120..201L |
Abstract
Based on 28 individual catalogues, in which the positions of optical
counterparts of extragalactic radio sources are listed, we compiled a
combined catalogue by means of a weighted least squares adjustment. The
catalogue is in the system of FK5/J2000.0. It consists of about five
hundred sources, among which there are 56 primary sources with position
uncertainties as 0.09". Comparisons show that the orientation
differences between optical and radio frames are A_1_=-0.013"+/-0.012",
A_2_=0.077"+/-0.012", A_3_=0.005" +/-0.009". Local relative deformations
are not obvious within the precision of ground-based optical
observations.
| Title: |
| A Complete Flux-Density--limited VLBI Survey of 293 Flat-Spectrum Radio Sources |
| Authors: |
| TAYLOR, G. B.; VERMEULEN, R. C.; READHEAD, A. C. S.; PEARSON, T. J.; HENSTOCK, D. R.; WILKINSON, P. N. |
| Journal: |
| Astrophysical Journal Supplement v.107, p.37 |
| Publication Date: |
| 11/1996 |
| Origin: |
| APJ; NED |
| ApJ Keywords: |
| GALAXIES: ACTIVE, GALAXIES: QUASARS: GENERAL, RADIO CONTINUUM: GALAXIES, SURVEYS |
| Bibliographic Code: |
| 1996ApJS..107...37T |
Abstract
We define a complete flux-density-limited sample of 293 flat-spectrum
sources-the Caltech-Jodrell Bank flat-spectrum (CIF) sample. The CIF
sample is designed to integrate the bulk of our existing VLBI survey
observations into a large, homogeneous database for statistical studies
of a broad range of astrophysical and cosmological issues. Here we
present 6 cm VLBA observations of the 18 sources that had not yet been
imaged with VLBI, and both 6 and 20 cm VLA observations of 186 sources
in the sample.
| Title: |
| The Redshift of an Extremely Red Object and the Nature of the Very Red Galaxy Population |
| Authors: |
| GRAHAM, JAMES R.; DEY, ARJUN |
| Journal: |
| Astrophysical Journal v.471, p.720 |
| Publication Date: |
| 11/1996 |
| Origin: |
| APJ; NED |
| ApJ Keywords: |
| GALAXIES: EVOLUTION, GALAXIES: PHOTOMETRY, GALAXIES: STELLAR CONTENT, GALAXIES: STRUCTURE, INFRARED: GALAXIES |
| Bibliographic Code: |
| 1996ApJ...471..720G |
Abstract
Infrared surveys have discovered a significant population of bright (K
<~ 19) extremely red (R - K ~> 6) objects. Little is known about the
properties of these objects on account of their optical faintness (R ~>
24). Here we report deep infrared imaging and spectroscopy of one of the
extremely red objects (EROs) discovered by Hu & Ridgway in the field of
the z = 3.79 quasar PC 1643+4631A. The infrared images were obtained in
0.5" seeing and show that the object (denoted HR 10) is not a
dynamically relaxed elliptical galaxy dominated by an old stellar
population as was previously suspected, but instead has an asymmetric
morphology suggestive of either a disk or an interacting system. The
infrared spectrum of HR 10 shows a single, possibly broad emission
feature at 1.60 microns, which we identify as H{alpha} + [N II] at z =
1.44. The luminosity and width of this emission line indicates either
intense star formation (~20 h^-2^ M_sun_ yr^-1^) or the presence of an
active nucleus. Based on the rest frame UV-optical spectral energy
distribution, the luminosity of HR 10 is estimated to be 3-8 L^*^. The
colors of HR 10 are unusually red for a galaxy (at z = 1.44 the age of
HR 10 is at most 2-8 Gyr depending on cosmology) and indicate that HR 10
is dusty. HR 10 is detected weakly at radio wavelengths; this is
consistent with either the starburst or active galactic nucleus
hypothesis. If HR 10 is a typical representative of its class, EROs are
numerous and represent a significant component of the luminous objects
in the universe at z ~ 1.5.
| Title: |
| Soft X-Ray Properties of Seyfert Galaxies in the ROSAT All-Sky Survey |
| Authors: |
| RUSH, BRIAN; MALKAN, MATTHEW A.; FINK, HENNER H.; VOGES, WOLFGANG |
| Journal: |
| Astrophysical Journal v.471, p.190 |
| Publication Date: |
| 11/1996 |
| Origin: |
| APJ; NED |
| ApJ Keywords: |
| GALAXIES: ISM, GALAXIES: SEYFERT, INFRARED: GALAXIES, X-RAYS: GALAXIES |
| Bibliographic Code: |
| 1996ApJ...471..190R |
Abstract
We present the results of ROSAT All-Sky Survey observations of Seyfert
and IR luminous galaxies from the extended 12 micron galaxy sample and
the optically selected CfA sample. Detections are available for 80%
(44/55) of the Seyfert 1's and 34% (23/67) of the Seyfert 2's in the 12
micron sample, and for 76% (26/34) of the Seyfert 1's and 38% (6/16) of
the Seyfert 2's in the CfA sample. Roughly half of the Seyfert galaxies
(mostly Seyfert 1's) have been fitted to an absorbed power-law model,
yielding an average photon index of {GAMMA} = 2.26 +/- 0.11 for 43
Seyfert 1's and {GAMMA} = 2.45 +/- 0.18 for 10 Seyfert 2's, with both
types having a median value of 2.3. The soft X-ray luminosity correlates
with the 12 micron luminosity, with Seyfert 1's having relatively more
soft X-ray emission than Seyfert 2's of similar mid-IR luminosities by a
factor of 1.6 +/- 0.3. Several physical interpretations of these results
are discussed, including the standard unified model for Seyfert
galaxies. Infrared luminous non- Seyferts are shown to have similar
distributions of soft X-ray luminosity and X-ray-to-IR slope as Seyfert
2's, suggesting that some of them may harbor obscured active nuclei (as
has already been shown to be true for several objects) and/or that the
soft X-rays from some Seyferts 2's may be nonnuclear. A soft X-ray
luminosity function (XLF) is calculated for the 12 micron sample, which
is described well by a single power law with a slope of - 1.75. The
normalization of this XLF agrees well with that of a hard X-ray selected
sample. Several of our results, related to the XLF and the X- ray-to-IR
relation, are shown to be consistent with the hard X-ray observations of
the 12 micron sample by Barcons et al.
| Title: |
| The Global Rate and Efficiency of Star Formation in Spiral Galaxies as a Function of Morphology and Environment |
| Authors: |
| YOUNG, JUDITH S.; ALLEN, LORI; KENNEY, JEFFREY D. P.; LESSER, AMY; ROWND, BROOKS |
| Journal: |
| Astronomical Journal v.112, p.1903 |
| Publication Date: |
| 11/1996 |
| Origin: |
| AJ |
| AJ/ApJ Keywords: |
| STARS: FORMATION, GALAXIES: SPIRAL, GALAXIES: FUNDAMENTAL PARAMETERS |
| Bibliographic Code: |
| 1996AJ....112.1903Y |
Abstract
CCD images of H{alpha} and R-band emission in 120 spiral galaxies were
obtained using the now-retired No. 1-0.9 m telescope of Kitt Peak
National Observatory. These images were used to derive the distribution
and total flux of continuum-subtracted H{alpha} line emission, and
therefore the H{alpha} surface brightnesses and high mass star formation
rates in these galaxies. We find a small but significant variation in
the mean H{alpha} surface brightness for spiral galaxies along the
Hubble sequence; the Sd-Ir galaxies exhibit a mean H{alpha} surface
brightness 1.4 times higher than the Sbc-Scd galaxies, and 2-3 times
higher than the Sa-Sb galaxies. Estimates for the total formation rate
for high mass stars have been compared with global molecular gas masses
to determine the global efficiency of high mass star formation (=
L_*_/M_gas_) as a function of morphological type and environment. We
find that the mean efficiency of high mass star formation in this
sample of spiral galaxies shows little dependence on morphological type
for galaxies of type Sa through Scd, although there is a wide range in
star formation efficiencies within each type. Galaxies in disturbed
environments (i.e., strongly interacting systems) are found to have a
mean star formation efficiency ~4 times higher than in isolated spiral
galaxies, uncorrected for extinction. This confirms previous findings
(Young et al. 1986a,b; Sanders et al. 1986; Solomon & Sage 1988; Tinney
et al. 1990), based on the far-infrared luminosity rather than the
H{alpha} luminosity to trace the rate of high mass star formation, that
the mean star formation efficiency among isolated galaxies is
significantly lower than that among interacting systems. This result
provides further confirmation that the rate of high mass star formation
is reasonably well traced by both the H{alpha} and the IR luminosity in
spiral galaxies. </PRE>
| Title: |
| First results from the ISOCAM parallel mode. |
| Authors: |
| SIEBENMORGEN, R.; ABERGEL, A.; ALTIERI, B.; BIVIANO, A.; BLOMMAERT, J.A.D.L.; BOULADE, O.; CESARSKY, C.; GALLAIS, P.; GUEST, S.; KESSLER, M.F.; METCALFE, L.; OKUMURA, K.; OTT, S.; PERAULT, M.; POLLOCK, A.M.T.; PRUSTI, T.; SAUVAGEON, A.; STARCK, J.L. |
| Journal: |
| Astronomy and Astrophysics, v.315, p.L169-L172 |
| Publication Date: |
| 11/1996 |
| Origin: |
| A&A via CDS |
| A&A Keywords: |
| SURVEYS, GALAXY: STRUCTURE, INFRARED: STARS |
| Abstract Copyright: |
| (c) 1996: Astronomy & Astrophysics |
| Bibliographic Code: |
| 1996A&A...315L.169S |
Abstract
We present first results of a survey being made in a broad-band
6.75{mu}m filter using the ISOCAM infrared camera in its parallel mode
at ~6" resolution. So far we have analysed a sky area of ~1.375deg^2^
down to a limiting flux of 5 mJy and detected a total of 287 objects.
The final survey will cover a sky area of ~33deg^2^, most of which will
be done in staring mode, to which we have restricted ourselves in the
present paper. The final catalogue should reach a typical sensitivity
limit of ~1 mJy. We estimate that at the detection limit 99% of the
objects will have a galactic origin.
| Title: |
| A survey for high-redshift radio-loud quasars: optical spectroscopy of S<~0.2 Jy, flat-spectrum radio sources |
| Authors: |
| HOOK, I. M.; MCMAHON, R. G.; IRWIN, M. J.; HAZARD, C. |
| Affiliation: |
| AA(UC Berkeley Astronomy Department, Berkeley, CA 94720, USA ), AB(Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK ), AC(Royal Greenwich Observatory, Madingley Road, Cambridge CB3 0EZ, UK ), AD(Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK ) |
| Journal: |
| Monthly Notices of the Royal Astronomical Society, Volume 282, Issue 4, pp. 1274-1298. |
| Publication Date: |
| 10/1996 |
| Origin: |
| MNRAS |
| MNRAS Keywords: |
| SURVEYS, QUASARS: GENERAL, RADIO CONTINUUM: GALAXIES |
| Abstract Copyright: |
| (c) 1996 The Royal Astronomical Society |
| Bibliographic Code: |
| 1996MNRAS.282.1274H |
Abstract
We present optical spectroscopic data for a complete sample of 161
S_5GHz>=0.2 Jy, flat-spectrum radio sources. The sources were observed
as part of a survey for high-redshift, radio-loud quasars, and were
selected for spectroscopic follow-up based on criteria of red optical
colour and unresolved optical counterpart, as measured from APM scans of
POSS-I plates. 13 objects from the spectroscopic sample were found to be
radio-loud quasars with z<~3, of which two were previously known. We
give positions, E(red) magnitudes, O-E colours, 5-GHz radio fluxes,
radio spectral indices, optical spectra and redshifts where possible for
the spectroscopic sample. We also give finding charts for the z<~3 QSOs.
The highest redshift object found is a QSO with z=4.30 (GB1508+5714, the
subject of an earlier Letter). The sample also contains a z=3.05 QSO,
GB1759+7539, which is optically very luminous (E=16.1). In addition,
spectra are given for 18 S_5GHz>=0.2 Jy, flat-spectrum radio sources
that do not form part of the complete sample.