On the Spin of the Black Hole in IC 10 X-1
Abstract
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 ~ 10-15 Msun and a*>0.8. If the mass of IC 10 X-1's black hole is comparable, then its spin is likewise high.
Keywords
Cite
@article{arxiv.1512.03414,
title = {On the Spin of the Black Hole in IC 10 X-1},
author = {James F. Steiner and Dominic J. Walton and Javier A. Garcia and Jeffrey E. McClintock and Silas G. T. Laycock and Matthew J. Middleton and Robin Barnard and Kristin K. Madsen},
journal= {arXiv preprint arXiv:1512.03414},
year = {2016}
}
Comments
27 manuscript pages, 7 figures, 2 tables, submitted to ApJ