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{M}⊙ and {a}*\gt 0.8. If the mass of IC 10 X-1's black hole is comparable, then its spin is likewise high.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 2016
- DOI:
- 10.3847/0004-637X/817/2/154
- arXiv:
- arXiv:1512.03414
- Bibcode:
- 2016ApJ...817..154S
- Keywords:
-
- accretion;
- accretion disks;
- black hole physics;
- stars: individual: IC 10 X–1;
- X-rays: binaries;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 27 manuscript pages, 7 figures, 2 tables, submitted to ApJ