Stellar Distributions around a Supermassive Black Hole: Strong-segregation Regime Revisited

Itai Linial*, Re’em Sari

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


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 / dm ∝ m γ , stars with a specific orbital energy x = GM /r − v 2/2 are scattered primarily by stars of mass m d(x) ∝ x −5/(4γ+10) that dominate the scattering of both lighter and heavier species at that energy. Stars of mass m d(x) are exponentially rare at energies lower than x, and follow a density profile n ( x ′ ) ∝ x ′ 3 / 2 at energies x ′ > x . Our solution predicts a negligible flow of stars through energy space for all mass species, similarly to the conclusions of Bahcall & Wolf, but in contrast to the assumptions of Alexander & Hopman. This is the first analytic solution that smoothly transitions between regimes where different stellar masses dominate the scattering.

Original languageAmerican English
Article number101
JournalAstrophysical Journal
Issue number2
StatePublished - 1 Dec 2022

Bibliographical note

Funding Information:
The authors would like to thank Nicholas Stone for useful discussions and suggestions. This research was partially supported by an ISF grant. I.L. acknowledges support from the Adams Fellowship.

Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.


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