High Velocity Outflows in Narrow Absorption Line Quasars

TL;DR

This study investigates high velocity outflows in Narrow Absorption Line quasars using X-ray observations, revealing differences from Broad Absorption Line quasars and supporting a geometric outflow model.

Contribution

It provides new X-ray observational evidence for the outflow geometry in NAL quasars and compares their properties with BAL quasars and other quasars.

Findings

NAL quasars have lower X-ray absorption than BAL quasars.

Differences in alpha_ox distributions suggest different viewing angles.

UV absorption is indicated by positive Dalpha_ox values.

Abstract

The current paradigm for the AGN phenomenon is a central engine that consists of an inflow of material accreting in the form of a disk onto a supermassive black hole. Observations in the UV and optical find high velocity ionized material outflowing from the black hole. We present results from Suzaku and XMM-Newton observations of a sample of intrinsic NAL quasars with high velocity outflows. Our derived values of the intrinsic column densities of the X-ray absorbers are consistent with an outflow scenario in which NAL quasars are viewed at smaller inclination angles than BAL quasars. We find that the distributions of alpha_ox and Dalpha_ox of the NAL quasars of our sample differ significantly from those of BAL quasars and SDSS radio-quiet quasars. The NAL quasars are not significantly absorbed in the X-ray band and the positive values of Dalpha_ox suggest absorption in the UV band. The positive values of Dalpha_ox of the intrinsic NAL quasars can be explained in a geometric scenario where our lines of sight towards the compact X-ray hot coronae of NAL quasars do not traverse the absorbing wind whereas lines of sight towards their UV emitting accretion disks do intercept the outflowing absorbers.