Cluster temperature profiles and Sunyaev-Zeldovich observations

Galaxy clusters are not isothermal, and the radial temperature dependence will affect the cluster parameters derived through the observation of the Sunyaev–Zeldovich (SZ) effect. We show that the derived peculiar velocity will be systematically shifted by 10–20 per cent. For future all-sky surveys one cannot rely on the observationally expensive X-ray observations to remove this systematic error, but should instead reach for sufficient angular resolution to perform a deprojection in the SZ spectra. The Compton-weighted electron temperature is accurately derived through SZ observations.