scholarly journals VLA Observations of Ultraluminous IRAS Galaxies: Active Nuclei or Starbursts?

1996 ◽  
Vol 460 ◽  
pp. 225 ◽  
Author(s):  
Thomas Crawford ◽  
Jonathan Marr ◽  
Bruce Partridge ◽  
Michael A. Strauss
Keyword(s):  
Galaxies Active

Are All Elliptical Galaxies Active? (Poster paper)

1994 ◽  
pp. 446-447 ◽  
Author(s):  
Elaine M. Sadler ◽  
Bruce Slee
Keyword(s):  
Elliptical Galaxies ◽  
Poster Paper ◽  
Galaxies Active

Radio-continuum sources in nearby and bright E/S0 galaxies - Active nuclei versus star formation

1991 ◽  
Vol 101 ◽  
pp. 148 ◽  
Author(s):  
J. M. Wrobel ◽  
D. S. Heeschen
Keyword(s):  
Star Formation ◽  
Radio Continuum ◽  
S0 Galaxies ◽  
Galaxies Active

scholarly journals THE CO(J=2-1)/CO(J=1-0) Luminosity Ratio in the Orion Giant Molecular Clouds

1994 ◽  
Vol 140 ◽  
pp. 232-233
Author(s):  
Seiichi Sakamoto ◽  
Tetsuo Hasegawa ◽  
Masahiko Hayashi ◽  
Toshihiro Handa ◽  
Tomoharu Oka
Keyword(s):  
Molecular Clouds ◽  
Giant Molecular Clouds ◽  
Large Area ◽  
Active Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
First Results ◽  
Galaxies Active

AbstractThe first results of large-area mapping observations of nearby giant molecular clouds in the CO(J=2-1) emission are presented. The CO(J=2-1)/CO(J=1-0) luminosity ratio is 0.75 and 0.62 for the Orion A and B clouds, respectively. These values are consistent with those observed typically in disks of galaxies (−0.6), and are significantly lower than large values (≳1) often observed in active star-forming regions in galaxies. Active star-forming regions in galaxies cannot be explained by ensemble of Orion-like GMCs; they may contain a different population of molecular clouds with high J-2-1/J=1-0 luminosity ratio.

scholarly journals The eROSITA Final Equatorial-Depth Survey (eFEDS). A multiwavelength view of WISE mid-infrared galaxies/active galactic nuclei

2021 ◽  
Author(s):  
Y. Toba ◽  
T. Liu ◽  
T. Urrutia ◽  
M. Salvato ◽  
J. Li ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Infrared Galaxies ◽  
Mid Infrared ◽  
Galaxies Active

High-Energy Radiation From Active Galactic Nuclei

1994 ◽  
Vol 142 ◽  
pp. 923-928
Author(s):  
Marek Sikora
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
High Energy ◽  
Radiation Mechanisms ◽  
High Energy Radiation ◽  
Energy Radiation ◽  
X Ray ◽  
Radiation Properties ◽  
Galaxies Active

AbstractTwo recent findings concerning high-energy radiation properties of active galactic nuclei—discovery of breaks in hard X-ray spectra of Seyfert galaxies, and discovery of huge fluxes of hard gamma rays from blazars—seem to press us to change our standard views about radiation production in these objects. I review briefly the existing radiation models, confront them with the newest observations, and discuss newly emerging theoretical pictures which attempt to account for the discoveries.Subject headings: galaxies: active — galaxies: nuclei — radiation mechanisms: nonthermal

VLBI Imaging of Luminous Infrared Galaxies: Active Galactic Nucleus Cores in Markarian 231, UGC 5101, and NGC 7469

2003 ◽  
Vol 592 (2) ◽  
pp. 804-818 ◽  
Author(s):  
Carol J. Lonsdale ◽  
Colin J. Lonsdale ◽  
Harding E. Smith ◽  
Philip J. Diamond
Keyword(s):  
Active Galactic Nucleus ◽  
Infrared Galaxies ◽  
Luminous Infrared Galaxies ◽  
Ngc 7469 ◽  
Galaxies Active

scholarly journals Emission lines in early-type galaxies: active nuclei or stars?

2011 ◽  
Vol 529 ◽  
pp. A126 ◽  
Author(s):  
A. Capetti ◽  
R. D. Baldi
Keyword(s):  
Emission Lines ◽  
Early Type ◽  
Galaxies Active

scholarly journals X-ray detections of submillimetre galaxies: active galactic nuclei versus starburst contribution

2013 ◽  
Vol 431 (1) ◽  
pp. 662-682 ◽  
Author(s):  
S. P. Johnson ◽  
G. W. Wilson ◽  
Q. D. Wang ◽  
C. C. Williams ◽  
K. S. Scott ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
X Ray ◽  
Galaxies Active

scholarly journals Star formation history in barred spiral galaxies – active galactic nucleus feedback

2017 ◽  
Vol 469 (3) ◽  
pp. 3722-3737 ◽  
Author(s):  
Fidèle Robichaud ◽  
David Williamson ◽  
Hugo Martel ◽  
Daisuke Kawata ◽  
Sara L. Ellison
Keyword(s):  
Star Formation ◽  
Active Galactic Nucleus ◽  
Spiral Galaxies ◽  
Star Formation History ◽  
Formation History ◽  
Barred Spiral Galaxies ◽  
Galaxies Active

scholarly journals What Powers Ultra-Luminous IRAS Galaxies?

1996 ◽  
Vol 175 ◽  
pp. 215-216
Author(s):  
R.B. Partridge ◽  
J. Marr ◽  
T. Crawford ◽  
M. Strauss
Keyword(s):  
Active Galactic Nuclei ◽  
Thermal Emission ◽  
Galactic Nuclei ◽  
Far Infrared ◽  
Radio Flux ◽  
Very Large Array ◽  
Radio Wavelength ◽  
Tight Correlation ◽  
Galaxies Active

I report here centimeter–wavelength observations carried out at the Very Large Array (VLA) to help resolve two questions. First, what is the source of the far infrared (FIR) emission in infrared-luminous IRAS galaxies, active nuclei or more widely distributed star formation? And what physics underlies the tight correlation (Helou et al., 1985) between FIR and radio flux? To test potential answers to these questions, we believe it is important to study the most luminous IRAS galaxies. We selected 39 for study from the ultraluminous catalog of Strauss et al.(1990 and 1992). All sources had FIR luminosity ≥ 1011.4 L⊙. Radio wavelength observations of these systems provide several advantages. First, in the radio there is no obscuration, so we can “see” the active galactic nuclei, if present. Radio spectral indices can distinguish between synchrotron and thermal emission. And finally, observations at the VLA provide sub–kpc resolution. We observed these sources with the VLA in its C configuration. At 1460 MHz, the effective resolution was ≃ 15″; and ≃ 4″ at 4860 MHz. We made follow-up observations on 24 sources in the A configuration with resolution at 4860 MHz of ≃ 0″.5 (or 300–800 h–1 pc for these sources).

Sign in / Sign up

Export Citation Format

Share Document