Measurements of Sunyaev‐Zel’dovich Effect Scaling Relations for Clusters of Galaxies

We present new measurements of the Sunyaev-Zel'dovich (SZ) effect fromclusters of galaxies using the Sunyaev-Zel'dovich Infrared Experiment (SuZIEII). We combine these new measurements with previous cluster observations withthe SuZIE instrument to form a sample of 15 clusters of galaxies. For thissample we calculate the central Comptonization, y, and the integrated SZ fluxdecrement, S, for each of our clusters. We find that the integrated SZ flux isa more robust observable derived from our measurements than the centralComptonization due to inadequacies in the spatial modelling of theintra-cluster gas with a standard Beta model. This is highlighted by comparingour central Comptonization results with values calculated from measurementsusing the BIMA and OVRO interferometers. On average, the SuZIE calculatedcentral Comptonizations are approximately 60% higher in the cooling flowclusters than the interferometric values, compared to only approximately 12%higher in the non-cooling flow clusters. We believe this discrepancy to be inlarge part due to the spatial modelling of the intra-cluster gas. From ourcluster sample we construct y-T and S-T scaling relations. The y-T scalingrelation is inconsistent with what we would expect for self-similar clusters;however this result is questionable because of the large systematic uncertaintyin the central Comptonization. The S-T scaling relation has a slope andredshift evolution consistent with what we expect for self-similar clusterswith a characteristic density that scales with the mean density of theuniverse. We rule out zero redshift evolution of the S-T relation at 90%confidence.Comment: Accepted to Astrophysical Journal. 52 pages, 14 tables, 7 figures ;replaced to match ApJ accepted versio