COLA. III. Radio Detection of Active Galactic Nucleus in Compact Moderate Luminosity Infrared Galaxies

September 2010 • 2010ApJ...720..555P

Authors • Parra, R. • Conway, J. E. • Aalto, S. • Appleton, P. N. • Norris, R. P. • Pihlström, Y. M. • Kewley, L. J.

Abstract • We present results from 4.8 GHz Very Large Array (VLA) and global very long baseline interferometry (VLBI) observations of the northern half of the moderate FIR luminosity (median L _IR = 10^11.01 L _sun) COLA sample of star-forming galaxies. VLBI sources are detected in a high fraction (20/90) of the galaxies observed. The radio luminosities of these cores (~10²¹ W Hz^-1) are too large to be explained by radio supernovae or supernova remnants and we argue that they are instead powered by active galactic nuclei (AGNs). These sub-parsec scale radio cores are preferentially detected toward galaxies whose VLA maps show bright 100-500 parsec scale nuclear radio components. Since these latter structures tightly follow the FIR to radio-continuum correlation for star formation, we conclude that the AGN-powered VLBI sources are associated with compact nuclear starburst environments. The implications for possible starburst-AGN connections are discussed. The detected VLBI sources have a relatively narrow range of radio luminosity consistent with models in which intense compact Eddington-limited starbursts regulate the gas supply onto a central supermassive black hole. The high incidence of AGN radio cores in compact starbursts suggests little or no delay between the starburst phase and the onset of AGN activity.

Links

• PREPRINT http://arxiv.org/abs/1006.2740
• NED https://ned.ipac.caltech.edu/uri/NED::InRefcode/2010ApJ...720..555P
• ELECTR https://iopscience.iop.org/article/10.1088/0004-637X/720/1/555
• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2010ApJ...720..555P
• PDF https://iopscience.iop.org/article/10.1088/0004-637X/720/1/555/pdf
• DATA http://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/720/555