Physical and kinematical properties of the X-ray absorber in the broad absorption line quasar APM 08279+5255

TL;DR

This study re-analyzed X-ray spectra of the high-redshift BAL quasar APM 08279+5255, revealing a two-absorber model with ionized outflowing gas and consistent iron overabundance, advancing understanding of quasar absorption features.

Contribution

First detailed photoionization modeling of APM 08279+5255's X-ray spectrum, unifying previous observations with a two-absorber outflow model.

Findings

Two absorbers with distinct ionization states and column densities

High-ionization component outflowing at ~0.18c

Consistent Fe/O overabundance in both observations

Abstract

We have re-analyzed the X-ray spectra of the gravitational lensed high-redshift BAL QSO APM 08279+5255, observed with the XMM-Newton and Chandra observatories. Previous studies (Hasinger et al. 2002; Chartas et al. 2002) detected unusual, highly-ionized iron absorption features, but differed in their interpretation of these features, regarding the kinematical and ionization structure. We seek one physical model that can be successfully applied to both observations. For the first time we have performed detailed photoionization modeling on the X-ray spectrum of APM 08279+5255. The absorbing gas in APM 08279+5255 can be represented by a two-absorbers model with column densities N_H(1)~7x10^{22} cm^-2, N_H(2)~6x10^{22} cm^-2, and ionization parameters logxi(1)~1.5 and logxi(2)~3, with one of them (the high-ionization component) outflowing at v~0.18(\pm 0.01)c, carrying large amount of gas out of the system. We find that the Chandra spectrum of APM 08279+5255 requires the same Fe/O ratio overabundance (previously) indicated by the XMM-Newton observation, showing that both absorber components underwent similar chemical evolution and/or have similar origin.