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Paper: Evidence for an Intermediate Mass Black Hole in Omega Centauri
Volume: 352, New Horizons in Astronomy: Frank N. Bash Symposium 2005
Page: 269
Authors: Noyola, E.; Gebhardt, K.; Bergmann, M.
Abstract: The globular cluster ω Cen is one of the largest and most massive members of the galactic system. However, its classification as a globular cluster has been challenged making it a candidate for being the stripped core of an accreted dwarf galaxy; this together with the fact that it has one of the largest velocity dispersions for star clusters in our galaxy makes it an interesting candidate for harboring an intermediate mass black hole. We measure the surface brightness profile, and we find a central power-law cusp of slope −0.08. We analyze Gemini GMOS-IFU kinematic data for a 5″ x 500″ field centered on the cluster, as well as for a field 14″ away. We detect a clear rise in the velocity dispersion from 20 km/s at 14″ to 25 km/s in the center. An isotropic, spherical dynamical model requires a rise in the central M/L of a factor of three. Assuming a constant M/L for the stars, this rise implies a black hole of mass of 5 x 104 MSolar.
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