Non-thermal cluster emissions: a simultaneous interpretation of the central soft X-ray excess and WMAP's non-detection of the Sunyaev-Zel'dovich Effect

WMAP's first year non-detection of the Sunyaev-Zel'dovich effect (SZE) among a sample of 31 rich Abell clusters is interpreted in terms of conventional physics. It is already widely believed that the central soft X-ray excess found in some clusters cannot be of thermal origin, due to problems with rapid gas cooling, but may arise from inverse-Compton scattering between intracluster relativistic electrons and the cosmic microwave background. We demonstrate that higher energy electrons drawn from the same power-law spectrum as that responsible for the soft excess may also synchrotron radiate in the intracluster magnetic field of strength B $\lesssim$ 1~$\mu$G to produce cluster microwave emissions in the WMAP passbands that account for the missing SZE flux. There is in fact no significant discrepancy between the model parameters that account for either phenomena. This strengthens the likelihood of prevailing non-thermal activities in at least some clusters. The key point is that by merely invoking an intracluster population of cosmic rays having the same properties as those of our Galaxy, the microwave synchrotron flux is already within a factor of five from the expected SZE flux. The electrons may originate from AGN jet injection, then distributed cluster-wide with accompanying {\it in situ} Fermi acceleration, by Alfven waves