Sarah White (Curtin University)

Sarah White Colloquium: Evidence for AGN-powered radio emission in Radio-Quiet Quasars

Marsfield Lecture Theatre

Abstract

Studying the interplay of accretion and star formation is crucial to our understanding of galaxy evolution. As we probe low radio luminosities, the two main populations are star-forming galaxies and radio-quiet quasars (RQQs). How they contribute to the total radio emission is under debate, with previous studies arguing that star formation dominates. In this talk I will describe two RQQ samples that demonstrate the importance of accretion-related radio emission in these objects. The first sample is selected from the VISTA Deep Extragalactic Observations (VIDEO) survey, whose depth allows the study of very low accretion rates and/or lower-mass black holes. A second sample is obtained from the Spitzer-Herschel Active Galaxy Survey, spanning a factor of ~100 in optical luminosity over a narrow redshift range at z ~ 1. This enables evolutionary effects to be decoupled when comparisons are made with the VIDEO sample. Using radio data from the Karl G. Jansky Very Large Array (JVLA), I find further support that the AGN makes a significant contribution to the radio emission in RQQs. In addition, the levels of accretion and star formation appear to be weakly correlated with each other, and with optical luminosity.