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http://hdl.handle.net/20.500.12386/31265
Title: | X-Ray Observations of a [C II]-bright, z = 6.59 Quasar/Companion System | Authors: | Connor, Thomas Bañados, Eduardo Mazzucchelli, Chiara Stern, Daniel DECARLI, ROBERTO Fan, Xiaohui Farina, Emanuele Paolo LUSSO, ELISABETA Neeleman, Marcel Walter, Fabian |
Issue Date: | 2020 | Journal: | THE ASTROPHYSICAL JOURNAL | Number: | 900 | Issue: | 2 | First Page: | 189 | Abstract: | We present deep Chandra observations of PSO J231.6576-20.8335, a quasar at redshift z = 6.59 with a nearby (∼8 proper kpc) companion galaxy. The Atacama Large Millimeter/submillimeter Array observed both the quasar and companion to be bright in [C II], and the system has significant extended Lyα emission around the quasar, suggesting that a galaxy merger is ongoing. Unlike previous studies of two similar systems, and despite observing the system with Chandra for 140 ks, we do not detect the companion in X-rays. The quasar itself is detected, but only ${13.3}_{-3.7}^{+4.8}$ net counts are observed. From a basic spectral analysis, the X-ray spectrum of the quasar is soft (hardness ratio of ${ \mathcal H }{ \mathcal R }=-{0.60}_{-0.27}^{+0.17}$ , power-law index of ${\rm{\Gamma }}={2.6}_{-0.9}^{+1.0}$ ), which results in a rest-frame X-ray luminosity comparable to other bright quasars ( ${L}_{2\mbox{--}10}={1.09}_{-0.70}^{+2.20}\times {10}^{45}\ \mathrm{erg}\ {{\rm{s}}}^{-1}$ ) despite the faint observed X-ray flux. We highlight two possible interpretations of this result: the quasar has a steep value of Γ—potentially related to observed ongoing Eddington accretion—thereby pushing much of the emission out of our observed band, or the quasar has a more normal spectrum (Γ ∼ 2) but is therefore less X-ray luminous ( ${L}_{2\mbox{--}10}\sim 0.6\times {10}^{45}\ \mathrm{erg}\ {{\rm{s}}}^{-1}$ ). | URI: | http://hdl.handle.net/20.500.12386/31265 | URL: | https://iopscience.iop.org/article/10.3847/1538-4357/abaab9 https://api.elsevier.com/content/abstract/scopus_id/85093499291 |
ISSN: | 0004-637X | DOI: | 10.3847/1538-4357/abaab9 | Bibcode ADS: | 2020ApJ...900..189C | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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File | Description | Size | Format | |
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2007.14571.pdf | preprint | 975.77 kB | Adobe PDF | View/Open |
Connor_2020_ApJ_900_189.pdf | [Administrators only] | 787.55 kB | Adobe PDF |
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