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1999ApJ...524....9B - Astrophys. J., 524, 9-21 (1999/October-2)
A comparison of simple mass estimators for galaxy clusters.
BRAINERD T.G., OAXACA W.C., GOLDBERG D.M. and VILLUMSEN J.V.
Abstract (from CDS):
We define the total cluster mass to be the mass contained within a three-dimensional radius r200 of the cluster centers, where r200 is the radius inside which the mean interior overdensity is equal to 200. Under this definition the classical virial estimator yields a good measurement of the total cluster mass, although it is systematically underestimated by ∼10%. This result suggests that, at least in the limit of ideal data, the virial estimator is quite robust to deviations from pure spherical symmetry and the presence of substructure within a cluster. The dynamical mass estimate based upon a measurement of the cluster velocity dispersion and an assumption of an isothermal potential yields a poor measurement of the total cluster mass, underestimating it by ∼40% for the case in which σv is computed from an average over the entire cluster. The weak lensing estimate yields a very good measurement of the total cluster mass, provided that the mean shear used to determine the equivalent cluster velocity dispersion is computed from an average of the lensing signal over the entire cluster (i.e., the mean shear is computed interior to a projected cluster radius of R200).
Abstract Copyright: ∼
Journal keyword(s): Cosmology: Theory - Cosmology: Dark Matter - Galaxies: Clusters: General - Cosmology: Gravitational Lensing - Cosmology: Large-Scale Structure of Universe - body simulations
Simbad objects: 4
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