Is there a hard tail in the coma cluster X-ray spectrum?

Abstract

We report results from a re-analysis of the BeppoSAX observation of Coma and from the analysis of a second, yet unpublished observation of the same object. From our re-analysis of the first observation we find that the statistical evidence for a hard tail is about 2σ. From the analysis of the second observation which, thanks to the lower background and the longer exposure time, is characterized by a larger signal-to-noise we find no evidence for a hard tail. From the upper limit on the flux of the hard tail, using the standard Inverse Compton formulae, we derive a lower limit for the magnetic of ∼0.2-0.4 μGauss consistent with Faraday rotation measurements.