scholarly journals High Spatial Resolution Near-IR Tip/Tilt Imaging of “Warm” Ultraluminous Infrared Galaxies

1999 ◽  
Vol 186 ◽  
pp. 363-363
Author(s):  
J.A. Surace ◽  
D.B. Sanders
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Compact Star ◽  
Dust Emission ◽  
Host Galaxies ◽  
Infrared Galaxies ◽  
Star Forming ◽  
Compact Source ◽  
Near Ir ◽  
Ultraluminous Infrared Galaxies

We present results from high spatial resolution (FWHM ≈ 0.3–0.5″) near-IR (1.6 and 2.1μm) imaging of a complete sample of ultraluminous infrared galaxies (ULIGs) chosen to have “warm” mid-IR colors (f25/f60 > 0.2) characteristic of AGN. In conjunction with our WFPC2 imaging program (Surace et al. 1998), we have found that nearly all of these systems are advanced mergers with complex nuclear morphologies. The extended underlying galaxies are detected in each system at H and K′, and are found to have luminosities of a few L∗, similar to quasars (McLeod & Rieke 1994). Many of the circumnuclear star-forming knots seen at optical wavelengths have been detected. Based on model SEDs, their bolometric luminosities appear similar to those of the extended nuclear starbursts seen in other, less-luminous interacting systems (i.e. NGC 4038/9). Each ULIG is increasingly dominated at long wavelengths by a compact source which we identify as a putative active nucleus. The optical/near-IR colors of these putative nuclei are more extreme than the most infrared-active starburst galaxies, yet are identical to “far-IR loud” quasars which are in turn similar to optical quasars with significant hot (800 K) dust emission. Half of the ULIGs have dereddened nuclear near-IR luminosities comparable to those of QSOs, while the others resemble Seyferts; this may be an effect of patchy extinction and scattering. Similarities between the putative ULIG nuclei and QSO nuclei, the underlying host galaxies, and the apparent young age of the ULIGs (as evidenced by their compact star-forming knots) support the evolution of “warm” ULIGs into optical QSOs.

scholarly journals Atomic Hydrogen Gas Images of QSO Host Galaxies

2002 ◽  
Vol 199 ◽  
pp. 122-126
Author(s):  
J. Lim ◽  
P.T.P. Ho
Keyword(s):  
Atomic Hydrogen ◽  
Hydrogen Gas ◽  
Significant Fraction ◽  
Host Galaxies ◽  
Infrared Galaxies ◽  
Parent Population ◽  
Tidal Interactions ◽  
Ultraluminous Infrared Galaxies

We present the first neutral atomic hydrogen (HI) gas images of QSO host galaxies. The results come from our ongoing survey of all twenty-three QSOs at redshifts z < 0.07 visible from the VLA. Our images show tidal interactions in all of the QSO host galaxies detected in HI, even when no such interactions are clearly visible in the optical. The results are not consistent with the suggestion by Sanders et al. (1988a, 1988b) that ultraluminous infrared galaxies, the vast majority of which are later-stage mergers, are the parent population of a significant fraction of radio-quiet QSOs. Instead, our results suggest that QSOs reside in a wide variety of interacting environments.

scholarly journals AGN Absorption Linked to Host Galaxies

2013 ◽  
Vol 9 (S304) ◽  
pp. 319-322
Author(s):  
Stéphanie Juneau
Keyword(s):  
Star Formation Rate ◽  
Formation Rate ◽  
Far Infrared ◽  
Host Galaxies ◽  
Infrared Galaxies ◽  
Nuclear Activity ◽  
X Ray ◽  
Star Forming ◽  
Diagnostic Diagram ◽  
X Ray Absorption

AbstractMultiwavelength identification of AGN is crucial not only to obtain a more complete census, but also to learn about the physical state of the nuclear activity (obscuration, efficiency, etc.). A panchromatic strategy plays an especially important role when the host galaxies are star-forming. Selecting far-Infrared galaxies at 0.3<z<1, and using AGN tracers in the X-ray, optical spectra, mid-infrared, and radio regimes, we found a twice higher AGN fraction than previous studies, thanks to the combined AGN identification methods and in particular the recent Mass-Excitation (MEx) diagnostic diagram. We furthermore find an intriguing relation between AGN X-ray absorption and the specific star formation rate (sSFR) of the host galaxies, indicating a physical link between X-ray absorption and either the gas fraction or the gas geometry in the hosts. These findings have implications for our current understanding of both the AGN unification model and the nature of the black hole-galaxy connection.

scholarly journals No supernovae detected in two long-duration gamma-ray bursts

2007 ◽  
Vol 365 (1854) ◽  
pp. 1269-1275 ◽  
Author(s):  
D Watson ◽  
J.P.U Fynbo ◽  
C.C Thöne ◽  
J Sollerman
Keyword(s):  
Massive Star ◽  
Gamma Ray ◽  
Compact Star ◽  
Gamma Ray Bursts ◽  
Host Galaxy ◽  
Core Collapse ◽  
Host Galaxies ◽  
Star Forming ◽  
Long Duration ◽  
Spiral Arm

There is strong evidence that long-duration gamma-ray bursts (GRBs) are produced during the collapse of a massive star. In the standard version of the collapsar model, a broad-lined and luminous Type Ic core-collapse supernova (SN) accompanies the GRB. This association has been confirmed in observations of several nearby GRBs. Recent observations show that some long-duration GRBs are different. No SN emission accompanied the long-duration GRBs 060505 and 060614 down to limits fainter than any known Type Ic SN and hundreds of times fainter than the archetypal SN 1998bw that accompanied GRB 980425. Multi-band observations of the early afterglows, as well as spectroscopy of the host galaxies, exclude the possibility of significant dust obscuration. Furthermore, the bursts originated in star-forming galaxies, and in the case of GRB 060505, the burst was localized to a compact star-forming knot in a spiral arm of its host galaxy. We find that the properties of the host galaxies, the long duration of the bursts and, in the case of GRB 060505, the location of the burst within its host, all imply a massive stellar origin. The absence of an SN to such deep limits therefore suggests a new phenomenological type of massive stellar death.

scholarly journals VLBI OH maser polarimetry with the Australian Long Baseline Array: the star-forming region G340.054–0.244

2007 ◽  
Vol 3 (S242) ◽  
pp. 64-65
Author(s):  
I. Bains ◽  
J. Caswell ◽  
A. M. S. Richards ◽  
C. Phillips ◽  
S. Tingay ◽  
...  
Keyword(s):  
Spectral Line ◽  
Spatial Resolution ◽  
Radio Astronomy ◽  
High Velocity ◽  
High Spatial Resolution ◽  
Polarimetric Observation ◽  
Polarization Structure ◽  
Star Forming ◽  
Long Baseline ◽  
The Subject

AbstractUntil recently, high spatial resolution full Stokes maser polarimetry was the sole domain of northern interferometers and a wealth of sources in the far south remained unexplored due to a lack of suitable instrumentation having both high spatial and high velocity resolution. The Australia Telescope Long Baseline Array (LBA) has now switched to disk-based software correlation, permitting full Stokes observing in spectral line mode with velocity channels which are sufficiently narrow to sample usefully the polarization structure. To illustrate the utility of this valuable addition to radio astronomy, we present preliminary results of the first such polarimetric observation, the subject of which are the OH masers in the star-forming region G340.054–0.244.

scholarly journals High-spatial resolution SED of NGC 1068 from near-IR to radio

2008 ◽  
Vol 485 (1) ◽  
pp. 33-39 ◽  
Author(s):  
S. F. Hönig ◽  
M. A. Prieto ◽  
T. Beckert
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Near Ir ◽  
Ngc 1068

scholarly journals The Nature of the Energy Source in LINERs

1997 ◽  
Vol 159 ◽  
pp. 477-484
Author(s):  
L. Colina ◽  
A. Koratkar
Keyword(s):  
Minor Role ◽  
Host Galaxies ◽  
Infrared Galaxies ◽  
Star Forming ◽  
Luminous Infrared Galaxies ◽  
Star Forming Regions ◽  
Resolution Imaging ◽  
Imaging And Spectroscopy ◽  
A Minor ◽  
High Spatial Resolution Imaging

AbstractLINERs are found in ~30% of all bright galaxies, including luminous infrared galaxies. They form a heterogeneous class powered by a variety of ionizing mechanisms such as low-luminosity AGNs, starbursts, shocks, or any combination of these.In early-type spirals, LINERs are powered by a low-luminosity AGN, or by an AGN surrounded by circumnuclear star-forming regions. In luminous infrared galaxies, LINERs are powered by starbursts with associated wind-related extended shocks, and an AGN may play a minor role, if any. LINERs in some FR I radio galaxies show a strong evidence for the presence of a massive central black hole, and there are indications for the existence of shocks in the nuclear disks of these galaxies. Yet, the dominant ionizing mechanism for LINERs in radio-quiet ellipticals and FR I host galaxies is still unclear.Multifrequency high spatial resolution imaging and spectroscopy are essential to discriminate among the different ionizing mechanisms present in LINERs.

scholarly journals A High Spatial Resolution X‐Ray and Hα Study of Hot Gas in the Halos of Star‐forming Disk Galaxies. II. Quantifying Supernova Feedback

2004 ◽  
Vol 606 (2) ◽  
pp. 829-852 ◽  
Author(s):  
David K. Strickland ◽  
Timothy M. Heckman ◽  
Edward J. M. Colbert ◽  
Charles G. Hoopes ◽  
Kimberly A. Weaver
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Disk Galaxies ◽  
X Ray ◽  
Star Forming ◽  
Hot Gas ◽  
Supernova Feedback
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