2014/05/31 by Rachael M. Kratzer, Gordon T. Richards · 1 citation
Physics and Astronomy · #Accretion (finance) #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Emission spectrum #Galaxies: Formation, Evolution, Phenomena #Line (geometry) #Luminosity #Quasar #Redshift #Sky #Spectral line #astro-ph.GA #astro-ph.HE
paper · pdf · doi:10.1088/0004-6256/149/2/61
published as Astron. J. 149 (2015) 61 · 55 pages, 28 figures, accepted to AJ
arxiv created 2015/01/10 · openalex publication_date 2015/01/19 · arxiv updated 2015/02/05 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We investigate the evolution of both the radio-loud fraction (RLF) and (using stacking analysis) the mean radio loudness of quasars. We consider how these properties evolve as a function of redshift and luminosity, black hole (BH) mass and accretion rate, and parameters related to the dominance of a wind in the broad emission-line region. We match the FIRST source catalog to samples of luminous quasars (both spectroscopic and photometric), primarily from the Sloan Digital Sky Survey. After accounting for catastrophic errors in BH mass estimates at high redshift, we find that both the RLF and the mean radio luminosity increase for increasing BH mass and decreasing accretion rate. Similarly, both the RLF and mean radio loudness increase for quasars that are argued to have weaker radiation line driven wind components of the broad emission-line region. In agreement with past work, we find that the RLF increases with increasing optical/UV luminosity and decreasing redshift, while the mean radio loudness evolves in the exact opposite manner. This difference in behavior between the mean radio loudness and the RLF in may indicate selection effects that bias our understanding of the evolution of the RLF; deeper surveys in the optical and radio are needed to resolve this discrepancy. Finally, we argue that radio-loud (RL) and radio-quiet (RQ) quasars may be parallel sequences, but where only RQ quasars at one extreme of the distribution are likely to become RL, possibly through slight differences in spin and/or merger history.