Unveiling the X-ray/UV properties of disk winds in active galactic nuclei using broad and mini-broad absorption line quasars

TL;DR

This study analyzes X-ray and UV properties of disk winds in active galactic nuclei, revealing complex spectra influenced by significant absorption and variability, supporting the presence of radiation-driven accretion disk winds in quasars.

Contribution

It provides a uniform analysis of XMM-Newton observations of BAL and mini-BAL quasars, highlighting the role of absorption and variability in their spectra, and supports the disk wind model.

Findings

Spectra are complex and deviate from simple power laws.

Absorption is more significant than reflection in spectral shaping.

Large column densities of ionised gas are inferred.

Abstract

We present the results of the uniform analysis of 46 XMM-Newton observations of six BAL and seven mini-BAL QSOs belonging to the Palomar-Green Quasar catalogue. Moderate-quality X-ray spectroscopy was performed with the EPIC-pn, and allowed to characterise the general source spectral shape to be complex, significantly deviating from a power law emission. A simple power law analysis in different energy bands strongly suggests absorption to be more significant than reflection in shaping the spectra. If allowing for the absorbing gas to be either partially covering the continuum emission source or to be ionised, large column densities of the order of $10^{22-24}$ cm$^{-2}$ are inferred. When the statistics was high enough, virtually every source was found to vary in spectral shape on various time scales, from years to hours. All in all these observational results are compatible with radiation driven accretion disk winds shaping the spectra of these intriguing cosmic sources.