Stellar Distributions Around a Supermassive Black Hole: Strong Segregation Regime Revisited

Itai Linial, Re'em Sari

Submitted on 29 June 2022


We present a new analytical solution to the steady-state distribution of stars close to a central supermassive black hole of mass M in the center of a galaxy. Assuming a continuous mass function of the form dN/dmmγ, stars with a specific orbital energy x=GM/rv2/2 are scattered primarily by stars of mass md(x)x5/(4γ+10) that dominate the scattering of both lighter and heavier species at that energy. Stars of mass md(x) are exponentially rare at energies lower than x, and follow a density profile n(x)x3/2 at energies xx. Our solution predicts a negligible flow of stars through energy space for all mass species, similarly to the conclusions of Bahcall & Wolf (1977), but in contrast to the assumptions of Alexander & Hopman (2009). This is the first analytic solution which smoothly transitions between regimes where different stellar masses dominate the scattering.


Comment: 8 pages, 1 figure. Submitted to ApJ

Subject: Astrophysics - Astrophysics of Galaxies