Narrow, intrinsic C IV absorption in quasars as it relates to outflows, orientation, and radio properties

Abstract

This work provides evidence that a large fraction of C IV narrow absorption lines (NALs) seen along the line of sight to distant quasars are due to accretion disc winds, while also seeking to understand the relationship between NALs and certain quasar-intrinsic properties. We extend the results from past work in the literature using ∼105 000 NALs from a sample of ∼58 000 SDSS quasars. The primary results of this work are summarized as follows: (1) the velocity distribution (dN/dβ) of NALs is not a function of radio loudness (or even detection) once marginalized by optical/UV luminosity; (2) there are significant differences in the number and distribution of NALs as a function of both radio spectral index and optical/UV luminosity, and these two findings are not entirely interdependent; (3) improvements in quasar systemic redshift measurements and differences in the NAL distribution as a combined function of optical luminosity and radio spectral index together provide evidence that a significant portion of NALs are due to outflows; (4) the results are consistent with standard models of accretion disc winds governed by the LUV-αox relationship and line-of-sight orientation indicated by radio spectral index, and (5) possibly support a magnetically arrested disc model as an explanation for the semistochastic nature of strong radio emission in a fraction of quasars.