paper

Radio Loud and Radio Quiet Quasars

arXiv:1608.04586 · doi:10.3847/0004-637X/831/2/168

Abstract

We discuss 6 GHz JVLA observations covering a volume-limited sample of 178 low redshift () optically selected QSOs. Our 176 radio detections fall into two clear categories: (1) About \% are radio-loud QSOs (RLQs) having spectral luminosities primarily generated in the active galactic nucleus (AGN) responsible for the excess optical luminosity that defines a \emph{bona fide} QSO. (2) The radio-quiet QSOs (RQQs) have and radio sizes , and we suggest that the bulk of their radio emission is powered by star formation in their host galaxies. "Radio silent" QSOs () are rare, so most RQQ host galaxies form stars faster than the Milky Way; they are not "red and dead" ellipticals. Earlier radio observations did not have the luminosity sensitivity needed to distinguish between such RLQs and RQQs. Strong, generally double-sided, radio emission spanning was found associated with 13 of the 18 RLQ cores having peak flux densities (). The radio luminosity function of optically selected QSOs and the extended radio emission associated with RLQs are both inconsistent with simple "unified" models that invoke relativistic beaming from randomly oriented QSOs to explain the difference between RLQs and RQQs. Some intrinsic property of the AGNs or their host galaxies must also determine whether or not a QSO appears radio loud.

Accepted for publication in Astrophysical Journal Supplements

References in corpus (11)

Cited by in corpus (62)