CTIO  > Science Talks  >  Abstracts

Amy Kimball
NAASC Post-doctoral Fellow
National Radio Astronomy Observatory
& NOAO South Visiting Astronomer
 

"The Radio Luminosity Function of Optically-Selected QSOs: Star Formation and AGNs"
 

Despite decades of study, it remains unclear whether there are distinct radio-loud and radio-quiet populations of quasi-stellar objects (QSOSs). New 6 GHz EVLA observations allow us for the first time to obtain nearly complete radio detections in a volume-limited, color-selected sample of 179 QSOs from the SDSS in the narrow redshift range 0.2 < z < 0.3. We were able to detect sources as faint as 20 microJy, which is equivalent to log(L_6GHz) = 21.5 at z=0.25, well below the radio luminosity, log(L_6GHz) = 22.5, that separates star-forming galaxies from radio-loud active galactic nuclei (AGNs) driven by accretion onto a super-massive black hole.  I will show that the radio luminosity function of QSOs, now fully characterized for the very first time, can be explained by the combination of two radio emission components, with AGN emission dominating at the bright end and starbursting host galaxies dominating at the faint end.