Sunyaev-Zel'dovich observations of a statistically complete sample of galaxy clusters with OCRA-p

We present 30-GHz Sunyaev-Zeldovich (SZ) observations of a statistically complete sample of galaxy clusters with the One Centimetre Receiver Array-prototype (OCRA-p). The clusters are the 18 most X-ray luminous clusters at z > 0.2 in the ROSAT Brightest Cluster Sample. We correct for contaminant radio sources via supplementary observations with the Green Bank Telescope, also at 30 GHz, and remove a cluster that is contaminated by an unresolved X-ray source. All 17 remaining clusters have central SZ effects with Comptonization parameter y0 exceeding 1.9 x 10(-4), and 13 are detected at significance >= 3 sigma. We use our data to examine scalings between y0 and X-ray temperature, X-ray luminosity and the X-ray mass proxy YX, and find good agreement with predictions from self-similar models of cluster formation, with an intrinsic scatter in y0 of about 25 per cent. We also comment on the success of the observations in the face of the contaminant source population, and the implications for upcoming cm-wave surveys.