ar X iv : a st ro - p h / 99 05 25 6 v 1 1 9 M ay 1 99 9 A Sunyaev - Zel ’ dovich Effect Survey for High Redshift Clusters

Interferometric observations of the Sunyaev-Zel'dovich Effect (SZE) toward clusters of galaxies provide sensitive cosmological probes. We present results from 1 cm observations (at BIMA and OVRO) of a large, intermediate redshift cluster sample. In addition, we describe a proposed, higher sensitivity array which will enable us to survey large portions of the sky. Simulated observations indicate that we will be able to survey one square degree of sky per month to sufficient depth that we will detect all galaxy clusters more massive than 2 × 10 14 h −1 50 M⊙, regardless of their redshift. We describe the cluster yield and resulting cosmological constraints from such a survey. Interactions between cosmic microwave background (CMB) photons and the hot, ionized plasma in galaxy clusters introduce changes in the spectrum of the CMB. At wavelengths of 1 cm we observe this Sunyaev-Zel'dovich Effect (SZE) [1] as a decrease in the intensity of the CMB; this decrement ∆T (R) at projected cluster radius R can be expressed as ∆T (R) T CMB = −2 σ T m e c 2 dl n e (l, R)k B T e (l, R) (1) where σ T is the Thomson cross section, m e c 2 is the electron rest mass, n e is the electron number density and k B is the Boltzmann constant. Note that the fractional change in the CMB temperature ∆T /T CMB is independent of redshift; it depends only on properties of the ICM. Higher order corrections to this expression and a consideration of the effects of cluster peculiar velocities on the CMB spectrum can be found elsewhere (e.g., [2]). The typical central decrement for a massive ∼ 10 15 M ⊙ galaxy cluster is ∼ 1 mK, and for typical radio telescope system temperatures the SZE decrement is only a few parts in 10 5 of the power detected by the receiver, making SZE observations challenging. Characteristics of radio interferometry 4 Chandra Fellow