On the Radio and Optical Luminosity Evolution of Quasars II - The SDSS Sample

TL;DR

This study analyzes the evolution of radio and optical luminosities in over 5000 quasars from SDSS and FIRST data, revealing strong positive evolution with redshift and a smooth distribution of radio loudness without bi-modality.

Contribution

It introduces a comprehensive analysis of quasar luminosity evolution and the true distribution of radio loudness, accounting for data truncations and correlations, using the Efron and Petrosian method.

Findings

Strong positive evolution in both radio and optical luminosities with redshift.

Radio evolution is somewhat greater than optical.

The intrinsic radio loudness distribution is smooth, with no bi-modality.

Abstract

We determine the radio and optical luminosity evolutions and the true distribution of the radio loudness parameter R, defined as the ratio of the radio to optical luminosity, for a set of more than 5000 quasars combining SDSS optical and FIRST radio data. We apply the method of Efron and Petrosian to access the intrinsic distribution parameters, taking into account the truncations and correlations inherent in the data. We find that the population exhibits strong positive evolution with redshift in both wavebands, with somewhat greater radio evolution than optical. With the luminosity evolutions accounted for, we determine the density evolutions and local radio and optical luminosity functions. The intrinsic distribution of the radio loudness parameter R is found to be quite different than the observed one, and is smooth with no evidence of a bi-modality in radio loudness. The results we find are in general agreement with the previous analysis of Singal et al. 2011 which used POSS-I optical and FIRST radio data.