Deriving the Mass Distribution of M87 from Globular Clusters
Abstract
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 nonparametric twointegral distribution function. We apply the method to a sample of 161 globular clusters in M87. We find that the mass within 32 kpc is (2.4+/0.6)×10^{12} M_{solar}, and the exponent of the density profile ρ~r^{α} in the range 10100 kpc is α=1.6+/0.4. The energy distribution suggests a few kinematically distinct groups of globular clusters. The anisotropy of the globular cluster velocity distribution cannot be determined reliably with the present data. Models fitted to an NFW potential yield similar mass estimates but cannot constrain the concentration radius r_{c} in the range 10500 kpc.
 Publication:

The Astrophysical Journal
 Pub Date:
 May 2006
 DOI:
 10.1086/501515
 arXiv:
 arXiv:astroph/0508463
 Bibcode:
 2006ApJ...643..210W
 Keywords:

 Galaxies: Fundamental Parameters;
 Galaxies: Individual: Messier Number: M87;
 Galaxies: Kinematics and Dynamics;
 Galaxies: Star Clusters;
 Methods: Statistical;
 Astrophysics
 EPrint:
 32 pages, 12 figures, accepted to publish in ApJ