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On the Spin of the Black Hole in IC 10 X-1

Steiner, James F. and Walton, Dominic J. and García, Javier A. and McClintock, Jeffrey E. and Laycock, Silas G. T. and Middleton, Matthew J. and Barnard, Robin and Madsen, Kristin K. (2016) On the Spin of the Black Hole in IC 10 X-1. Astrophysical Journal, 817 (2). Art. No. 154. ISSN 0004-637X.

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The compact X-ray source in the eclipsing X-ray binary IC 10 X–1 has reigned for years as ostensibly the most massive stellar-mass black hole, with a mass estimated to be about twice that of its closest rival. However, striking results presented recently by Laycock et al. reveal that the mass estimate, based on emission-line velocities, is unreliable and that the mass of the X-ray source is essentially unconstrained. Using Chandra and NuSTAR data, we rule against a neutron-star model and conclude that IC 10 X–1 contains a black hole. The eclipse duration of IC 10 X–1 is shorter and its depth shallower at higher energies, an effect consistent with the X-ray emission being obscured during eclipse by a Compton-thick core of a dense wind. The spectrum is strongly disk-dominated, which allows us to constrain the spin of the black hole via X-ray continuum fitting. Three other wind-fed black hole systems are known; the masses and spins of their black holes are high: M ~ 10 - 15M_☉ and ɑ_* > 0.8. If the mass of IC 10 X-1's black hole is comparable, then its spin is likewise high.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Steiner, James F.0000-0002-5872-6061
Walton, Dominic J.0000-0001-5819-3552
García, Javier A.0000-0003-3828-2448
Middleton, Matthew J.0000-0002-8183-2970
Madsen, Kristin K.0000-0003-1252-4891
Additional Information:© 2016. The American Astronomical Society. Received 2015 September 28; accepted 2015 December 14; published 2016 January 28. This research has made use of software provided by the Chandra X-ray Center (CXC). This work was made possible by Chandra Grant GO4-15051X. J.F.S. has been supported by the NASA Hubble Fellowship grant HST-HF-51315.01, and the NASA Einstein Fellowship grant PF5-160144. We thank the CXC helpdesk and Larry David for their advice on the Chandra data reductions. J.F.S. thanks R. Remillard and J. Homan for helpful discussions on NS spectral models. We thank the anonymous referee for helpful criticisms which have improved this paper. This research has made use of data obtained with the NuSTAR mission, a project led by the California Institute of Technology (Caltech), managed by the Jet Propulsion Laboratory (JPL) and funded by NASA, and has utilized the NuSTAR Data Analysis Software (nustardas) jointly developed by the ASI Science Data Center (ASDC, Italy) and Caltech (USA). Chandra ObsId 15803.
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
NASA Hubble FellowshipHST-HF-51315.01
NASA Einstein FellowshipPF5-160144
Subject Keywords:accretion, accretion disks; black hole physics; stars: individual (IC 10 X–1) ; X-rays: binaries
Issue or Number:2
Record Number:CaltechAUTHORS:20160128-120939504
Persistent URL:
Official Citation:James F. Steiner et al 2016 ApJ 817 154
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:64049
Deposited By: Ruth Sustaita
Deposited On:28 Jan 2016 22:54
Last Modified:09 Mar 2020 13:19

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