Suzaku Observations of Near-Relativistic Outflows in the BAL Quasar APM 08279+5255

TL;DR

This study uses Suzaku X-ray observations to confirm the presence of near-relativistic outflows in the high-redshift BAL quasar APM 08279+5255, revealing variable, high-velocity winds that contribute significant kinetic energy to the intergalactic medium.

Contribution

First detection of variable, near-relativistic outflows in a high-redshift BAL quasar using Suzaku, confirming previous findings and providing new insights into quasar feedback mechanisms.

Findings

Detection of broad absorption features at <2 keV and 7-12 keV

Outflow velocities between 0.1c and 0.6c

Absorption line variability on ~1 month timescale

Abstract

We present results from three Suzaku observations of the z=3.91 gravitationally lensed broad absorption line quasar APM 08279+5255. We detect strong and broad absorption at rest-frame energies of <2 keV (low-energy) and 7-12 keV (high-energy). The detection of these features confirms the results of previous long-exposure (80-90 ks) Chandra and XMM-Newton observations. The low and high-energy absorption is detected in both the back-illuminated (BI) and front-illuminated (FI) Suzaku XIS spectra (with an F-test significance of >99%). We interpret the low-energy absorption as arising from a low-ionization absorber with log NH~23 and the high-energy absorption as due to lines arising from highly ionized (2.75 < log xi < 4.0; where xi is the ionization parameter) iron in a near-relativistic outflowing wind. Assuming this interpretation we find that the velocities in the outflow range between 0.1c and 0.6c. We constrain the angle between the outflow direction of the X-ray absorber and our line of sight to be <36 degrees. We also detect likely variability of the absorption lines (at the >99.9% and >98% significance levels in the FI and BI spectra, respectively) with a rest-frame time scale of ~1 month. Assuming that the detected high-energy absorption features arise from Fe xxv, we estimate that the fraction of the total bolometric energy injected over the quasar's lifetime into the intergalactic medium in the form of kinetic energy to be >10%.