Redshift Dependence of the Cosmic Microwave Background Temperature from SunyaevZeldovich Measurements
Abstract
We have determined the cosmic microwave background temperature, T(z), at redshifts in the range 0.0230.546, from multifrequency measurements of the SunyaevZeldovich (SZ) effect toward 13 clusters. We extract the parameter α in the redshift scaling T(z) = T _{0}(1 + z)^{1α}, which contrasts the prediction of the standard model (α = 0) with that in nonadiabatic evolution conjectured in some alternative cosmological models. The statistical analysis is based on two main approaches: using ratios of the SZ intensity change, ∆I, thus taking advantage of the weak dependence of the ratios on intracluster gas properties, and using directly the ∆I measurements. In the former method, dependence on the Thomson optical depth and gas temperature is only second order in these quantities. In the second method, we marginalize over these quantities which appear to first order in the intensity change. The marginalization itself is done in two ways—by direct integrations and by a Monte Carlo Markov chain approach. Employing these different methods we obtain two sets of results that are consistent with α = 0, in agreement with the prediction of the standard model.
 Publication:

The Astrophysical Journal
 Pub Date:
 November 2009
 DOI:
 10.1088/0004637X/705/2/1122
 arXiv:
 arXiv:0909.2815
 Bibcode:
 2009ApJ...705.1122L
 Keywords:

 cosmic microwave background;
 cosmology: observations;
 galaxies: clusters: individual: A1656 A2204 A1689 A520 A2163 A773 A2390 A1835 A697 ZW3146 RXJ1347 CL0016+16 MS0451 ─ 0305;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 Accepted for publication in ApJ