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Connor_2019_ApJ_887_171.pdf
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Final Published Version
Author
Connor, ThomasBañados, Eduardo

Stern, Daniel

Decarli, Roberto
Schindler, Jan-Torge
Fan, Xiaohui
Farina, Emanuele Paolo
Mazzucchelli, Chiara
Mulchaey, John S.
Walter, Fabian

Affiliation
Univ Arizona, Steward ObservIssue Date
2019-12-18
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IOP PUBLISHING LTDCitation
Thomas Connor et al 2019 ApJ 887 171Journal
ASTROPHYSICAL JOURNALRights
Copyright © 2019. The American Astronomical Society. All rights reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Quasars at early redshifts (z > 6) with companion galaxies offer unique insights into the growth and evolution of the first supermassive black holes. Here, we report on a 150 ks Chandra observation of PSO.J308.0416-21.2339, a z = 6.23 quasar with a merging companion galaxy identified in [C II] and rest-frame UV emission. With 72.3(-8.6)(+9.6) net counts, we find that PSO.J308.0416-21.2339 is powerful (L-X = 2.31(-0.76)(+1.14) x 10(45) erg s(-1) cm(-2) in rest-frame 2.0-10.0 keV) yet soft (spectral power-law index Gamma = 2.39(-0.36)(+0.37) and optical-to-X-ray slope alpha(OX) = -1.41 +/- 0.11). In addition, we detect three hard-energy photons 2 ''.0 to the west of the main quasar, cospatial with the brightest UV emission of the merging companion. As no soft-energy photons are detected in the same area, this is potentially indicative of a highly obscured source. With conservative assumptions, and accounting for both background fluctuations and the extended wings of the quasar's emission, these photons only have a probability P = 0.021 of happening by chance. If confirmed by deeper observations, this system is the first high-redshift quasar and companion individually detected in X-rays and is likely a dual active galactic nucleus.ISSN
0004-637XVersion
Final published versionSponsors
STSCI/NASAae974a485f413a2113503eed53cd6c53
10.3847/1538-4357/ab5585