THE EFFECTS OF RELATIVISTIC CORRECTIONS ON COSMOLOGICAL PARAMETER ESTIMATIONS FROM SUNYAEV-ZELDOVICH EFFECT CLUSTER SURVEYS

摘要

Sunyaev-Zeldovich effect (SZE) cluster surveys are anticipated to yield tight constraints on cosmological parameters, such as the equation of state of dark energy. In this paper, we study the effect of relativistic corrections of the thermal SZE on the cluster number counts expected from a cosmological model and thus, assuming that other cosmological parameters are known to high accuracies, on the determination of the w-parameter and σ_8 from an SZE cluster survey, where w = p / ρ (with p the pressure and ρ the density of dark energy) and σ_8 is the rms of the extrapolated linear density fluctuation smoothed over 8 Mpc h~(-1). For the purpose of illustrating the effects of relativistic corrections, our analyses mainly focus on ν = 353 GHz and S_(lim) = 30 mJy, where ν and S_(lim) are the observing frequency and the flux limit of a survey, respectively. These observing parameters are relevant to the Planck survey. It is found that from two measurable quantities, the total number of SZE clusters and the number of clusters with redshift z ≥ 0.5, σ_8 and w can be determined to a level of +-1% and +-8%, respectively, with 1 σ uncertainties from a survey of 10,000 deg~2. Relativistic effects are important in determining the central values of σ_8 and w. If we choose the two quantities calculated relativ-istically from the flat cosmological model with σ_8 = 0.8284 and w = -0.75 as input, the derived σ_8 and w would be 0.819 and -0.81, respectively, if relativistic effects are wrongly neglected. The location of the resulting σ_8 and w in the σ_8-w plane is outside the 3 σ region around the real central σ_8 and w.