Triple Experiment Spectrum of the Sunyaev-Zel'dovich Effect in the Coma Cluster: H0

The Sunyaev-Zel'dovich (SZ) effect was previously measured in the Coma Cluster by the Owens Valley Radio Observatory and Millimeter and IR Testa Grigia Observatory experiments and recently also with the W ilkinson Microwave Anisotropy Probe satellite. We assess the consistency of these results and their implications on the feasibility of high-frequency SZ work with ground-based telescopes. The unique data set from the combined measurements at six frequency bands is jointly analyzed, resulting in a best-fit value for the Thomson optical depth at the cluster center, τ0 = (5.35 ± 0.67) × 10-3. The combined X-ray and SZ determined properties of the gas are used to determine the Hubble constant. For isothermal gas with a β density profile we derive H0 = 84 ± 26 km (s Mpc)-1; the (1 σ) error includes only observational SZ and X-ray uncertainties.