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  • A benchmark for extreme conditions of the multiphase interstellar medium in the most luminous hot dust-obscured galaxy at z  = 4.6
Title: A benchmark for extreme conditions of the multiphase interstellar medium in the most luminous hot dust-obscured galaxy at z  = 4.6
WISE J224607.6–052634.9 (W2246–0526) is a hot dust-obscured galaxy atz = 4.601, and the most luminous obscured quasar known to date. W2246–0526 harbors a heavily obscured supermassive black hole that is most likely accreting above the Eddington limit. We present observations with the Atacama Large Millimeter/submillimeter Array (ALMA) in seven bands, including band 10, of the brightest far-infrared (FIR) fine-structure emission lines of this galaxy: [OI]63 μm, [OIII]88 μm, [NII]122 μm, [OI]145 μm, [CII]158 μm, [NII]205 μm, [CI]370 μm, and [CI]609 μm. A comparison of the data to a large grid of CLOUDYradiative transfer models reveals that a high hydrogen density (nH ∼ 3 × 103cm−3) and extinction (AV ∼ 300 mag), together with extreme ionization (log(U) = − 0.5) and a high X-ray to UV ratio (αox ≥ −0.8) are required to reproduce the observed nuclear line ratios. The values ofαoxandUare among the largest found in the literature and imply the existence of an X-ray-dominated region (XDR). In fact, this component explains the a priori very surprising non-detection of the [OIII]88 μmemission line, which is actually suppressed, instead of boosted, in XDR environments. Interestingly, the best-fitted model implies higher X-ray emission and lower CO content than what is detected observationally, suggesting the presence of a molecular gas component that should be further obscuring the X-ray emission over larger spatial scales than the central region that is being modeled. These results highlight the need for multiline infrared observations to characterize the multiphase gas in high redshift quasars and, in particular, W2246–0526 serves as an extreme benchmark for comparisons of interstellar medium conditions with other quasar populations at cosmic noon and beyond.  more » « less
Award ID(s):
1847892 1910107
PAR ID:
10506238
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more » ; ; ; ; « less
Publisher / Repository:
Astronomy and Astrophysics
Date Published:
Journal Name:
Astronomy & Astrophysics
Volume:
682
ISSN:
0004-6361
Page Range / eLocation ID:
A166
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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