Imaging the Sunyaev–Zel'dovich Effect

We report on results of interferometric imaging of the Sunyaev–Zel'dovich Effect (SZE) with the OVRO and BIMA mm-arrays. Using low-noise cm-wave receivers on the arrays, we have obtained high quality images for 27 distant galaxy clusters. We review the use of the SZE as a cosmological tool. Gas mass fractions derived from the SZE data are given for 18 of the clusters, as well as the implied constraint on the matter density of the universe, Ω_M. We find Ω_Mh₁₀₀ ≤ 0.22^+0.05_-0.03. A best guess for the matter density obtained by assuming a reasonable value for the Hubble constant and also by attempting to account for the baryons contained in the galaxies as well as those lost during the cluster formation process gives Ω_M ~ 0.25. We also give preliminary results for the Hubble constant. Lastly, the power for investigating the high redshift universe with a non-targeted high sensitivity SZE survey is discussed and an interferometric survey is proposed.