A selection effect boosting the contribution from rapidly spinning black holes to the cosmic X-ray background

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dc.creator Vasudevan, R. V.
dc.creator Fabian, A. C.
dc.creator Reynolds, C. S.
dc.creator Aird, J.
dc.creator Dauser, T.
dc.creator Gallo, Luigi C.
dc.date.accessioned 2018-01-24T14:28:13Z
dc.date.available 2018-01-24T14:28:13Z
dc.date.issued 2016-05-11
dc.identifier.issn 0035-8711
dc.identifier.uri http://library2.smu.ca/handle/01/27254
dc.description Publisher's Version/PDF
dc.description.abstract The cosmic X-ray background (CXB) is the total emission from past accretion activity on to supermassive black holes in active galactic nuclei (AGN) and peaks in the hard X-ray band (30 keV). In this paper, we identify a significant selection effect operating on the CXB and flux-limited AGN surveys, and outline how they must depend heavily on the spin distribution of black holes. We show that, due to the higher radiative efficiency of rapidly spinning black holes, they will be over-represented in the X-ray background, and therefore could be a dominant contributor to the CXB. Using a simple bimodal spin distribution, we demonstrate that only 15 per cent maximally spinning AGN can produce 50 per cent of the CXB. We also illustrate that invoking a small population of maximally spinning black holes in CXB synthesis models can reproduce the CXB peak without requiring large numbers of Comptonthick AGN. The spin bias is even more pronounced for flux-limited surveys: 7 per cent of sources with maximally spinning black holes can produce half of the source counts. The detectability for maximum spin black holes can be further boosted in hard (>10 keV) Xrays by up to ∼60 per cent due to pronounced ionized reflection, reducing the percentage of maximally spinning black holes required to produce half of the CXB or survey number counts further. A host of observations are consistent with an over-representation of high-spin black holes. Future NuSTAR and ASTRO-H hard X-ray surveys will provide the best constraints on the role of spin within the AGN population. en_CA
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dc.description.provenance Made available in DSpace on 2018-01-24T14:28:13Z (GMT). No. of bitstreams: 1 Gallo_Luigi_C_article_2016.pdf: 1131625 bytes, checksum: cbe563f3ed561fe9b5aed0a78d3b22d4 (MD5) Previous issue date: 2016 en
dc.language.iso en en_CA
dc.publisher Oxford University Press en_CA
dc.relation.uri https://dx.doi.org/10.1093/mnras/stw363
dc.rights This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
dc.subject.lcsh Black holes (Astronomy)
dc.subject.lcsh Active galactic nuclei
dc.subject.lcsh Quasars
dc.title A selection effect boosting the contribution from rapidly spinning black holes to the cosmic X-ray background en_CA
dc.type Text en_CA
dcterms.bibliographicCitation Monthly Notices of the Royal Astronomical Society 458(2), 2012-2023. (2016) en_CA
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This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
 
Published Version: https://dx.doi.org/10.1093/mnras/stw363
 
 

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