The XRay Luminosity Function of Nearby Rich and Poor Clusters of Galaxies:A Cosmological Probe
Abstract
In this Letter, we present a new determination of the local (z<=0.09) Xray luminosity function (XLF) using a large, statistical sample of 294 Abell clusters and the ROSAT AllSky Survey. Despite the optical selection of this catalog, we find excellent agreement with other recent determinations of the local XLF. Given our large sample size, we have reduced errors by nearly a factor of 2 for L_{X(0.52.0keV)}>=10^{43}h^{2}_{50} ergs s^{1}. We combine our data with previous work to produce the most tightly constrained local determination of the XLF (over 3 orders of magnitude in L_{X}) in order to explore possible constraints imposed by the shape of the XLF on cosmological models. A set of currently viable cosmologies is used to construct theoretical XLFs assuming L~M^{p} and a σ_{8}Ω_{0} constraint based on the local Xray temperature function. We fit these models to our observed XLF and verify that the simplest adiabatic, analytic scaling relation disagrees strongly with observations. If we assume that clusters can be described by the preheated, constant core entropy models of Evrard & Henry, then the observed XLF is consistent only with 0.1<Ω_{0}<0.4 if the energy per unit mass in galaxies is roughly equal to the gas energy (i.e., if β~1).
 Publication:

The Astrophysical Journal
 Pub Date:
 May 1999
 DOI:
 10.1086/311996
 arXiv:
 arXiv:astroph/9903117
 Bibcode:
 1999ApJ...516L..53L
 Keywords:

 COSMOLOGY: OBSERVATIONS;
 GALAXIES: CLUSTERS: GENERAL;
 XRAYS: GENERAL;
 Cosmology: Observations;
 Galaxies: Clusters: General;
 XRays: General;
 Astrophysics
 EPrint:
 4 pages, 2 figures, accepted for publication in ApJ Letters. uses emulateapj.sty