The XMM deep survey in the CDF-S

IX. An X-ray outflow in a luminous obscured quasar at z ≈ 1.6

¹ Dipartimento di Fisica e Astronomia, Alma Mater Studiorum, Università degli Studi di Bologna, viale Berti Pichat 6/2, 40127, Bologna, Italy
e-mail: cristian.vignali@unibo.it
² INAF–Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
³ ICREA and Institut de Ciències del Cosmos (ICC), Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, 08028 Barcelona, Spain
⁴ Institute for Astronomy & Astrophysics, Space Applications & Remote Sensing, National Observatory of Athens, Palaia Penteli 15236 Athens, Greece
⁵ European Southern Observatory, Karl-Schwarzschild-Straße 2, 85748 Garching, Germany
⁶ Excellence Cluster Universe, Technische Universität München, Boltzmannstrasse 2, 85748 Garching, Germany
⁷ Instituto de Física de Cantabria (CSIC-UC), Avenida de los Castros, 39005 Santander, Spain
⁸ Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281, S9 9000 Gent, Belgium
⁹ Instituto de Radioastronomía y Astrofísica, IRAf, UNAM, Campus Morelia, A.P. 3-72, CP 58089, Mexico
¹⁰ Department of Astronomy & Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
¹¹ Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802, USA
¹² Department of Physics, Eberly College of Science, The Pennsylvania State University, University Park, PA 16802, USA
¹³ Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, 306 Santiago 22, Chile
¹⁴ Millennium Institute of Astrophysics, MAS, Nuncio Monseñor Sótero Sanz 100, Providencia, Santiago de Chile
¹⁵ Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, Colorado 80301, USA
¹⁶ INAF–Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monteporzio Catone, Roma, Italy
¹⁷ Department of Astronomy, University of Maryland, College Park, MD 20742-2421, USA
¹⁸ NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA

Received: 9 February 2015
Accepted: 21 August 2015

Abstract

In active galactic nuclei (AGN)-galaxy co-evolution models, AGN winds and outflows are often invoked to explain why super-massive black holes and galaxies stop growing efficiently at a certain phase of their lives. They are commonly referred to as the leading actors of feedback processes. Evidence of ultra-fast (v ≳ 0.05c) outflows in the innermost regions of AGN has been collected in the past decade by sensitive X-ray observations for sizable samples of AGN, mostly at low redshift. Here we present ultra-deep XMM-Newton and Chandra spectral data of an obscured (N_H≈ 2 × 10²³ cm^-2), intrinsically luminous (L_{2−10 keV}≈ 4 × 10⁴⁴ erg s^-1) quasar (named PID352) at z ≈ 1.6 (derived from the X-ray spectral analysis) in the Chandra Deep Field-South. The source is characterized by an iron emission and absorption line complex at observed energies of E ≈ 2−3 keV. While the emission line is interpreted as being due to neutral iron (consistent with the presence of cold absorption), the absorption feature is due to highly ionized iron transitions (FeXXV, FeXXVI) with an outflowing velocity of 0.14^+0.02_-0.06c, as derived from photoionization models. The mass outflow rate – ~2 M_⊙ yr^-1 – is similar to the source accretion rate, and the derived mechanical energy rate is ~9.5 × 10⁴⁴ erg s^-1, corresponding to 9% of the source bolometric luminosity. PID352 represents one of the few cases where indications of X-ray outflowing gas have been observed at high redshift thus far. This wind is powerful enough to provide feedback on the host galaxy.