Analytic study of mass segregation around a massive black hole

Uri Keshet; Clovis Hopman; Tal Alexander

doi:10.1088/0004-637X/698/1/L64

Analytic study of mass segregation around a massive black hole

Uri Keshet, Clovis Hopman, Tal Alexander

Research output: Contribution to journal › Article › peer-review

48 Scopus citations

Abstract

We analyze the distribution of stars of arbitrary mass function ξ(m) around a massive black hole (MBH). Unless ξ is strongly dominated by light stars, the steady-state distribution function approaches a power law in specific energy x ≡ -E/mσ² < x _max with index p = m/4M ₀, where E is the energy, σ is the typical velocity dispersion of unbound stars, and M ₀ is the mass averaged over mξx^p _max. For light-dominated ξ, p can grow as large as 3/2 - much steeper than previously thought. A simple prescription for the stellar density profile around MBHs is provided. We illustrate our results by applying them to stars around the MBH in the Milky Way.

Original language	English
Pages (from-to)	L64-L67
Journal	Astrophysical Journal
Volume	698
Issue number	1 PART 2
DOIs	https://doi.org/10.1088/0004-637X/698/1/L64
State	Published - 1 Jan 2009
Externally published	Yes

Keywords

Black hole physics
Galaxy: kinematics and dynamics
Stellar dynamics

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1088/0004-637X/698/1/L64

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abstract = "We analyze the distribution of stars of arbitrary mass function ξ(m) around a massive black hole (MBH). Unless ξ is strongly dominated by light stars, the steady-state distribution function approaches a power law in specific energy x ≡ -E/mσ2 < x max with index p = m/4M 0, where E is the energy, σ is the typical velocity dispersion of unbound stars, and M 0 is the mass averaged over mξxp max. For light-dominated ξ, p can grow as large as 3/2 - much steeper than previously thought. A simple prescription for the stellar density profile around MBHs is provided. We illustrate our results by applying them to stars around the MBH in the Milky Way.",

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N2 - We analyze the distribution of stars of arbitrary mass function ξ(m) around a massive black hole (MBH). Unless ξ is strongly dominated by light stars, the steady-state distribution function approaches a power law in specific energy x ≡ -E/mσ2 < x max with index p = m/4M 0, where E is the energy, σ is the typical velocity dispersion of unbound stars, and M 0 is the mass averaged over mξxp max. For light-dominated ξ, p can grow as large as 3/2 - much steeper than previously thought. A simple prescription for the stellar density profile around MBHs is provided. We illustrate our results by applying them to stars around the MBH in the Milky Way.

AB - We analyze the distribution of stars of arbitrary mass function ξ(m) around a massive black hole (MBH). Unless ξ is strongly dominated by light stars, the steady-state distribution function approaches a power law in specific energy x ≡ -E/mσ2 < x max with index p = m/4M 0, where E is the energy, σ is the typical velocity dispersion of unbound stars, and M 0 is the mass averaged over mξxp max. For light-dominated ξ, p can grow as large as 3/2 - much steeper than previously thought. A simple prescription for the stellar density profile around MBHs is provided. We illustrate our results by applying them to stars around the MBH in the Milky Way.

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KW - Galaxy: kinematics and dynamics

KW - Stellar dynamics

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Analytic study of mass segregation around a massive black hole

Abstract

Keywords

ASJC Scopus subject areas

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