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We describe our methods for measuring the Hubble constant from Ryle Telescope (RT) interferometric observations of the Sunyaev–Zel'dovich (SZ) effect from a galaxy cluster and observation of the cluster X-ray emission. We analyse the error budget in this method: as well as radio and X-ray random errors, we consider the effects of clumping and temperature differences in the cluster gas, of the kinetic SZ effect, of bremsstrahlung emission at radio wavelengths, of the gravitational lensing of background radio sources and of primary calibration error. Using RT, ASCA and ROSAT observations of the Abell 1413, we find that random errors dominate over systematic ones, and estimate H[sub 0]=57[sup +23][sub -16]kms[sup -1] Mpc[sup -1] for a an Ω[sub M]=1.0, Ω[sub Λ]=0.0 cosmology. [ABSTRACT FROM AUTHOR]

We have mapped the high-redshift (z=0.546) cluster Cl 0016+16 with the Ryle Telescope at 15 GHz. The Sunyaev–Zel'dovich decrement is clearly detected, and resolved. We combine our data with an X-ray image from ROSAT and a gas temperature from ASCA to estimate the Hubble constant H[sub 0]=69[sub -16][sup +21] km s[sup -1] Mpc[sup -1] for an Ω[sub M]=1.0 cosmology, or H[sub 0]=84[sub -19][sup +25] km s[sup -1] Mpc[sup -1] for Ω[sub M]=0.3 and Ω[sub Λ]=0.7. [ABSTRACT FROM AUTHOR]