Miguel Preto and Pau Amaro-Seoane 2010 ApJ 708 L42 doi:10.1088/2041-8205/708/1/L42
Miguel Preto1 and Pau Amaro-Seoane2,3
Show affiliationsWe present, for the first time, a clear N-body (NB) realization of the strong mass segregation solution for the stellar distribution around a massive black hole (MBH). We compare our NB results with those obtained by solving the orbit-averaged Fokker-Planck (FP) equation in energy space. The NB segregation is slightly stronger than in the FP solution, but both confirm the robustness of the regime of strong segregation when the number fraction of heavy stars is a (realistically) small fraction of the total population. In view of recent observations revealing a dearth of giant stars in the sub-parsec region of the Milky Way, we show that the timescales associated with cusp re-growth are not longer than (0.1 – 0.25) × Trlx (rh ). These timescales are shorter than a Hubble time for black holes masses M •
4 × 106 M ☉ and we conclude that quasi-steady, mass-segregated, stellar cusps may be common around MBHs in this mass range. Since extreme mass ratio inspirals detection rates by Laser Interferometer Space Antenna are expected to peak for M • ~ 4 × 105-106 M ☉, a good fraction of these events should originate from strongly segregated stellar cusps.
black hole physics; galaxies: nuclei; gravitational waves; stellar dynamics
Issue 1 (2010 January 1)
Received 2009 October 18, accepted for publication 2009 December 1
Published 2009 December 16
Miguel Preto and Pau Amaro-Seoane 2010 ApJ 708 L42
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