Magnified views of the ultrafast outflow of the z = 1.51 active galactic nucleus HS 0810+2554

Abstract

We present results from an observation of the gravitationally lensed z = 1.51 narrow absorption line (NAL) active galactic nucleus (AGN) HS 0810+2554 performed with the Chandra X-Ray Observatory. The factor of ∼100 lensing magnification of HS 0810+2554 makes this source exceptionally bright. Absorption lines are detected at rest-frame energies of ∼7.7 keV and ∼11.0 keV at ≳97% significance. By interpreting these lines to arise from highly ionized iron the implied outflow velocities of the X-ray absorbing gas corresponding to these lines are 0.13c and 0.41c, respectively. The presence of these relativistic outflows and the absence of any significant low-energy X-ray absorption suggest that a shielding gas is not required for the generation of the relativistic X-ray absorbing winds in HS 0810+2554. UV spectroscopic observations with VLT/UVES indicate that the UV absorbing material is outflowing at v UV ∼0.065c. Our analysis indicates that the fraction of the total bolometric energy released by HS 0810+2554 into the intergalactic medium (IGM) in the form of kinetic energy is εk = 1.0. An efficiency of greater than unity implies that magnetic driving is likely a significant contributor to the acceleration of this X-ray absorbing wind. We also estimate the mass-outflow rate of the strongest absorption component to be = 1.1 M yr-1. Assuming that the energetic outflow detected in the NAL AGN HS 0810+2554 is a common property of most AGN it would suggest that the X-ray absorbing wind may have a larger opening angle than previously thought. This has important consequences for estimating the feedback contribution of X-ray absorbing winds to the surrounding IGM. © 2014. The American Astronomical Society. All rights reserved..