Covering factors of the dusty obscurers in radio-loud and radio-quiet quasars

TL;DR

This study compares the covering factors of dusty obscurers in radio-loud and radio-quiet quasars, finding slight differences that are significant only at high Eddington ratios, with no strong dependence on other parameters.

Contribution

It provides the first comparative analysis of covering factors in radio-loud versus radio-quiet quasars using matched samples and infrared-to-bolometric luminosity ratios.

Findings

Covering factors are slightly smaller in radio-loud quasars.

Significant difference appears only at high Eddington ratios.

No strong dependence of covering factor on redshift or black hole mass.

Abstract

We compare covering factors of circumnuclear dusty obscurers in radio-loud and radio-quiet quasars. The radio-loud quasars are represented by a sample of FR II quasars obtained by cross-matching a catalog of the FR II radio sources selected by van Velzen et al. with the SDSS DR7 catalog of quasars. Covering factors of FR II quasars are compared with covering factors of the radio-quiet quasars matched with them in redshift, black hole mass, and Eddington-ratio. We found that covering factors, proxied by the infrared-to-bolometric luminosity ratio, are on average slightly smaller in FR II quasars than in radio-quiet quasars, however, this difference is statistically significant only for the highest Eddington ratios. For both samples, no statistically significant dependence of a median covering factor on Eddington ratio, black hole mass, nor redshift can be claimed.