For refcode 2004ApJ...607..202M: Retrieve 2461 NED objects in this reference. Please click here for ADS abstract
NED Abstract
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2004ApJ...607..202M
A Redshift Survey of Nearby Galaxy Groups: The Shape of the Mass Density
Profile
Andisheh Mahdavi and Margaret J. Geller
Abstract. We constrain the mass profile and orbital structure of nearby
groups and clusters of galaxies. Our method yields the joint probability
distribution of the density slope n, the velocity anisotropy {beta}, and
the turnover radius r_0_ for these systems. The measurement technique does
not use results from Nbody simulations as priors. We incorporate 2419 new
redshifts (included here) in the fields of 41 systems of galaxies with
z<0.04. The new groups have median velocity dispersion {sigma}=360 km
s^1^. We also use 979 archived redshifts in the fields of eight nearly
relaxed clusters with z<0.1. Within R<~2r_200_, the data are consistent
with a single powerlaw matter density distribution with slope n=1.8  2.2
for systems with {sigma}<470 km s^1^ and n=1.6  2.0 for those with
{sigma}>470 (95% confidence). We show that a simple, scalefree phasespace
distribution function (DF) f(E,L^2^) is proportional to
(E)^{alpha}1/2^L^2{beta}^ is consistent with the data as long as the
matter density has a cusp. Using this DF, matter density profiles with
constantdensity cores (n=0) are ruled out with better than 99.7%
confidence.
Keywords: Galaxies: Clusters: General, Galaxies: Kinematics and Dynamics,
Galaxies: Statistics
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