THE STARBURST-ACTIVE-GALACTIC-NUCLEUS CONNECTION: A SPITZER SEARCH FOR ACTIVE GALACTIC NUCLEI IN INFRARED-SELECTED STARBURST GALAXIES

Journal Article · Thu Oct 20 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/740/2/99; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21587356

Dixon, T G

We present observations of a sample of 28 luminous infrared galaxies (LIRGs) from the IRAS Bright Galaxy Catalog. These galaxies were previously observed by Goldader et al. using 2 {mu}m spectroscopy on UKIRT. They found that stellar population synthesis models constrained by the spectroscopic diagnostics implied star formation rates that accounted for their infrared luminosities, and there was also no spectroscopic evidence for 'buried' active galactic nuclei (AGNs) at 2 {mu}m. To search for evidence of AGNs buried deeply in extinction we have supplemented the UKIRT spectra with Spitzer mid-infrared (5.2-38.0 {mu}m) spectra. Using a variety of spectroscopic diagnostics we find that {approx}50% of the sample shows some evidence for an AGN. We also find that the luminosity of about {approx}(17 {+-} 4)% of our sample is probably dominated by emission from AGNs, and the remaining {approx}(80 {+-} 4)% have luminosities dominated by starbursts. Since {approx}50% of the sample shows some evidence of concurrent AGN and starburst activities this suggests that both AGNs and starbursts commonly coexist in the LIRGs' phase of evolution. The sample consists of galaxies that show no AGN signatures at wavelengths less than 2 {mu}m, so it appears that at wavelengths below 2 {mu}m extinction in these galaxies masks the detection of AGNs in these and other LIRGs.

• OSTI ID: 21587356
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 740; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CATALOGS
DOCUMENT TYPES
EMISSION
EVOLUTION
GALACTIC EVOLUTION
GALAXIES
GALAXY NUCLEI
LUMINOSITY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
STARS