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

Abstract

We present a new analytical solution to the steady-state distribution of stars close to a central supermassive black hole of mass $M_{\bullet }$ in the center of a galaxy. Assuming a continuous mass function of the form $dN/dm\propto m^{\gamma }$, stars with a specific orbital energy $x=G{M}_{\bullet }/r-v^2/2$ are scattered primarily by stars of mass $m_{\mathrm{d}}(x)\propto x^{-5/(4\gamma +10)}$ that dominate the scattering of both lighter and heavier species at that energy. Stars of mass $m_{\mathrm{d}}(x)$ are exponentially rare at energies lower than $x$, and follow a density profile $n(x^{\prime })\propto x^{\prime 3/2}$ at energies $x^{\prime }\gg x$. 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.

arXiv comment8 pages, 1 figure. Submitted to ApJ

References in corpus (19)

• Gravitational waves from scattering of stellar-mass black holes in galactic nuclei
• Strong mass segregation around a massive black hole
• Stellar Dynamics and Stellar Phenomena Near A Massive Black Hole
• The Distribution of Stars and Stellar Remnants at the Galactic Center
• Stellar Dynamics of Extreme-Mass-Ratio Inspirals
• On strong mass segregation around a massive black hole: Implications for lower-frequency gravitational-wave astrophysics
• An Overabundance of Black Hole X-Ray Binaries in the Galactic Center from Tidal Captures
• Rates of Stellar Tidal Disruption
• The Milky Way's nuclear star cluster: Old, metal-rich, and cuspy
• The impact of realistic models of mass segregation on the event rate of extreme-mass ratio inspirals and cusp re-growth
• The distribution of stars around the Milky Way's black hole III: Comparison with simulations
• A new Fokker-Planck approach for relaxation-driven evolution of galactic nuclei
• The Formation of Intermediate Mass Black Holes in Galactic Nuclei
• Direct N-body simulation of the Galactic centre
• Analytic study of mass segregation around a massive black hole
• The impact of mass segregation and star-formation on the rates of gravitational-wave sources from extreme mass ratio inspirals
• Spectroscopic Detection of a Cusp of Late-type Stars around the Central Black Hole in the Milky Way
• Tidal disruption events, main-sequence extreme-mass ratio inspirals and binary star disruptions in galactic nuclei
• Detectability of Gravitational Wave from a population of Inspiralling Black Holes in Milky Way Mass Galaxies

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• Segregation and Collisions in Galactic Nuclei: Rates of Destructive Events Near a Supermassive Black Hole
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