Cluster temperature profiles and Sunyaev-Zeldovich observations

Galaxy clusters are not iso-thermal, 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%. For future all-sky surveys one cannot rely on the observationally expensive X-ray observations to remove this systematic error, but one 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.