A Non-Parametric Estimate of the Mass of the Central Black Hole in the Galaxy

Dalia Chakrabarty(1,2), Prasenjit Saha(3)


(1) Department of Physics (Astrophysics), University of Oxford, Keble Road, Oxford OX1 3RH, UK
(2) Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 3RH, UK
(3) Astronomy Unit, School of Mathematical Sciences, Queen Mary and Westfield College, London E1 4NS, UK

Paper: ApJ, in press (July 2001)

EPrint Server: astro-ph/0103467


Abstract:

We estimate the mass of the central black hole in our Galaxy from stellar kinematical data published by Ghez et al. (1998) and Genzel et al. (2001). For this we develop a method, related to Merritt (1993), for non-parametrically reconstructing the mass profile and the stellar distribution function in the central region of the Galaxy from discrete kinematic data, including velocity errors. Models are searched using the Metropolis algorithm. We assume that the mass distribution is spherical and the stellar velocity distribution is isotropic, and devise a test of this assumption. From proper motions we obtain an enclosed mass of 2.0+/-0.7*106 M_o within the inner 0.0044pc, from radial velocities we obtain a mass of 2.2+1.6_-1.0*106M_o within 0.046pc and from three-dimensional velocities we obtain 1.8+0.4_-0.3*106M_o within 0.046pc.


Preprints available from the authors at dalia@astro.ox.ac.uk , or the raw TeX (no figures) if you click here.

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