Paper: astro-ph/0508463
Date: Mon, 22 Aug 2005 20:09:19 GMT (99kb)

Title: Deriving the mass distribution of M87 from globular clusters

Authors: Xiaoan Wu and Scott Tremaine

Comments: 32 pages, 13 figures, submitted to ApJ
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We describe a maximum-likelihood method for determining the mass distribution
in spherical stellar systems from the radial velocities of a population of
discrete test particles. The method assumes a parametric form for the mass
distribution and a non-parametric distribution function. We apply the method to
a sample of 161 globular clusters in M87. We find that the mass within 32 kpc
is $2.3\pm0.7\times 10^{12}$M${_\odot}$, and the exponent of the density
profile $\rho\propto r^{-\alpha}$ within 7-110 kpc is $\alpha=1.6\pm0.4$. The
anisotropy of the globular-cluster velocity distribution cannot be determined
reliably with the present data.

\\ ( http://arXiv.org/abs/astro-ph/0508463 , 99kb)