Yet another UFO in the X-ray spectrum of a high-z lensed QSO
Journal
Date Issued
2018
Author(s)
•
Vignali, C.
•
•
•
•
•
De Marco, B.
•
Chartas, G.
•
Giustini, M.
Abstract
Ultra-fast outflows (UFO) appear to be common in local active galactic nuclei
(AGN) and may be powerful enough ($\dot{E}_{kin}$$\geq$1\% of L$_{bol}$) to
effectively quench the star formation in their host galaxies. To test feedback
models based on AGN outflows, it is mandatory to investigate UFOs near the peak
of AGN activity, that is, at high-z where only a few studies are available to
date.
UFOs produce Fe resonant absorption lines measured above $\approx$7 keV. The
most critical problem in detecting such features in distant objects is the
difficulty in obtaining X-ray data with sufficient signal-to-noise. We
therefore selected a distant QSO that gravitational lensing made bright enough
for these purposes, the z=2.64 QSO MG J0414+0534, and observed it with
XMM-Newton for $\approx$78 ks.}
The X-ray spectrum of MG J0414+0534 is complex and shows signatures of cold
absorption (N$_{H}\approx$4$\times$10$^{22}$ cm$^{-2}$) and of the presence of
an iron emission line (E$\approx$6.4 keV, EW$=$95$\pm$53 eV) consistent with it
originating in the cold absorber. Our main result, however, is the robust
detection (more than 5$\sigma$) of an absorption line at E$_{int}\approx$9.2
keV (E$_{obs}\approx$2.5 keV observer frame). If interpreted as due to FeXXVI,
it implies gas outflowing at $v_{out}\approx$0.3c. To our knowledge, this is
the first detection of an UFO in a radio-loud quasar at z$\geq$1.5. We
estimated that the UFO mechanical output is
$\dot{E}_{kin}$$\approx$2.5$L_{bol}$ with
$\dot{p}_{out}/\dot{p}_{rad}\approx$17 indicating that it is capable of
installing significant feedback between the super-massive black hole (SMBH) and
the bulge of the host galaxy. We argue that this also suggests a magnetic
driving origin of the UFO.
Volume
610
Start page
L13
Issn Identifier
0004-6361
Rights
open.access
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