Probing the cosmic microwave background temperature using the Sunyaev-Zeldovich effect

Abstract

Abstract.We discuss the possibility of constraining the relation between redshift and temperature of the cosmic microwave background (CMB) using multifrequency Sunyaev-Zeldovich (SZ) observations. We have simulated a catalog of clusters of galaxies detected through their SZ signature assuming the sensitivities that will be achieved by the Planck satellite at 100, 143 and 353 GHz, taking into account the instrumental noise and the contamination from the Cosmic Infrared Background and from unresolved radiosources. We have parametrized the cosmological temperature-redshift law as T ∝ (1 + z)(1−a) . Using two sets of SZ flux density ratios (100/143 GHz, which is most sensitive to the parametrization of the T − z law, and 143/353 GHz, which is most sensitive to the peculiar velocities of the clusters) we show that it is possible to recover the T − z law assuming that the temperatures and redshifts of the clusters are known. From a simulated catalog of ∼1200 clusters, the parameter a can be recovered to an accuracy of 10 −2 . Sensitive SZ observations thus appear as a potentially useful tool to test the standard law. Most cosmological models predict a linear variation of the CMB temperature with redshift. The discovery of an alternative law would have profound implications on the cosmological model, implying creation of energy in a manner that would still maintain the black-body shape of the CMB spectrum at redshift zero.

Secondary anisotropies of the CMB

“…The spectral signature of the SZ effect can in principle probe the electron gas distribution and constrain any non-thermal electron population in the intracluster medium. Moreover multi-frequency SZ measurements might provide a novel way of constraining the CMB temperature and its evolution with redshift (Battistelli et al 2003, Horellou et al 2005). To achieve these goals, high precision measurements of the SZ effect will be needed over large areas of the sky.…”

Measurement of theTCMBevolution from the Sunyaev-Zel’dovich effect

“…This technique was originally proposed by Fabbri et al (1978) and Rephaeli (1980). Predictions for these measurement with Planck have been discussed by Horellou et al (2005) and de Martino et al (2012). They predicted, in an optimistic case, an uncertainty on the T CMB evolution of Δβ ∼ 0.011.…”

Constraints on the CMB temperature-redshift dependence from SZ and distance measurements

“…This method was applied to ground-based CMB observations [4,5], which demonstrated its potential. With a new generation of ground experiments becoming operational and a forthcoming all-sky survey of SZ clusters to be carried out by Planck [6], the potential of this method will come to fruition. At higher redshifts, z > 1, T (z) can be evaluated from the analysis of quasar absorption line spectra which show atomic and/or ionic fine structure levels excited by the photon absorption of the CMB radiation [7].…”