Spinning up black holes with super-critical accretion flows

A. Sądowski , M. Bursa , M. Abramowicz , W. Kluźniak , J. -P. Lasota (1) , R. Moderski , M. Safarzadeh

1 IAP - Institut d'Astrophysique de Paris

We study the process of spinning up black holes by accretion from slim disks for a wide range of accretion rates. We show that for super-Eddington accretion rates and low values of the viscosity parameter α ( ≲ 0.01) the limiting value of the dimensionless spin parameter a_∗ can reach values higher than a_∗ = 0.9978 inferred by Thorne in his seminal study. For Ṁ = 10 Ṁ_Edd and α = 0.01, spin equilibrium is reached at a_∗ = 0.9994. We show that the equilibrium spin value depends strongly on the assumed value of α. We also prove that for high accretion rates the impact of captured radiation on spin evolution is negligible.

Keywords: black hole physics; accretion; accretion disks; Astrophysics - High Energy Astrophysical Phenomena

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]

A. Sądowski, M. Bursa, M. Abramowicz, W. Kluźniak, J. -P. Lasota, et al.. Spinning up black holes with super-critical accretion flows. Astronomy and Astrophysics - A&A, 2011, 532, ⟨10.1051/0004-6361/201116702⟩. ⟨insu-03645942⟩