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We present new Ryle Telescope (RT) observations of the Sunyaev-Zel'dovich (SZ) decrement from the cluster Abell 773. The field contains a number of faint radio sources that required careful subtraction. We use ASCA observations to measure the gas temperature and a ROSAT HRI image to model the gas density distribution. Normalizing the gas distribution to fit the RT visibilities returns a value of H[sub 0] of 77[sup +19, sub -15] km s[sup -1] Mpc[sup -1] (1σ errors) for an Einstein-de Sitter universe, or 85[sup +20, sub -17] km[sup -1] Mpc[sup -1] for a flat model with Ω[sub Λ] = 0.7. The errors quoted include estimates of the effects of the principal errors: noise in the SZ measurement, gas temperature uncertainty and line-of-sight depth uncertainty. [ABSTRACT FROM AUTHOR]

Describes a maximum-likelihood approach to removing radio sources from observations of the Sunyaev-Zel'dovich effect. Removal of contaminating radio sources; Cosmology; Galaxies.