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A new way to measure supermassive black hole spin in accretion disc-dominated Active Galaxies

Done, C.; Jin, C.; Middleton, M.; Ward, M.J.

A new way to measure supermassive black hole spin in accretion disc-dominated Active Galaxies Thumbnail


C. Jin

M. Middleton


We show that disc continuum fitting can be used to constrain black hole spin in a subclass of narrow-line Seyfert 1 (NLS1) active galactic nuclei as their low mass and high mass accretion rate means that the disc peaks at energies just below the soft X-ray bandpass. We apply the technique to the NLS1 PG1244+026, where the optical/UV/X-ray spectrum is consistent with being dominated by a standard disc component. This gives a best estimate for black hole spin which is low, with a firm upper limit of a* <0.86. This contrasts with the recent X-ray determinations of (close to) maximal black hole spin in other NLS1 based on relativistic smearing of the iron profile. While our data on PG1244+026 do not have sufficient statistics at high energy to give a good measure of black hole spin from the iron line profile, cosmological simulations predict that black holes with similar masses have similar growth histories and so should have similar spins. This suggests that there is a problem either in our understanding of disc spectra, or/and X-ray reflection or/and the evolution of black hole spin.

Journal Article Type Article
Publication Date Jul 1, 2013
Deposit Date Jul 30, 2013
Publicly Available Date Jul 30, 2013
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Pages 1955-1963
Keywords Accretion, Accretion discs, Black hole physics, Galaxies: Seyfert, Ultraviolet: galaxies, X-rays: galaxies.
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Published Journal Article (619 Kb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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