The X-Rays wind connection in PG 2112+059

TL;DR

This study investigates the relationship between X-ray and UV properties of the BAL wind in quasar PG 2112+059, revealing correlations between BAL strength, UV redness, and X-ray absorption over multiple epochs.

Contribution

It provides new observational evidence linking X-ray and UV variability in BAL winds, supporting a wind-shield model with changing inclination and column densities.

Findings

Increased BAL equivalent widths correlate with redder UV spectra.

Soft X-ray emission dims as BALs grow stronger, indicating increased absorption.

Hard X-ray emission shows minor variations, with no significant BAL EW changes.

Abstract

We study the connection between the X-ray and UV properties of the broad absorption line (BAL) wind in the highly X-ray variable quasar PG 2112+059 by comparing Chandra-ACIS data with contemporaneous UV HST/STIS spectra in three different epochs. We observe a correlation whereby an increase in the equivalent-widths (EWs) of the BALs is accompanied by a redder UV spectrum. The growth in the BALs EWs is also accompanied by a significant dimming in soft X-ray emission (<2 keV), consistent with increased absorption. Variations in the hard X-ray emission (>2 keV) are only accompanied by minor spectral variations of the UV-BALs and do not show significant changes in the EW of BALs. These trends suggest a wind-shield scenario where the outflow inclination with respect to the line of sight is decreasing and/or the wind mass is increasing. These changes elevate the covering fraction and/or column densities of the BALs and are likely accompanied by a nearly contemporaneous increase in the column density of the shield.