Oscar Macías-Ramírez, Chris Gordon, Anthony M. Brown, Jenni Adams
Based on three years of Fermi Large Area Telescope (LAT) gamma-ray data of the Virgo cluster, evidence for an extended emission associated with dark matter pair annihilation has been reported by Han et al. [1]. After an in depth spatial and temporal analysis, we argue that the tentative evidence for a gamma-ray excess from the Virgo cluster is mainly due to the appearance of a population of previously unresolved gamma-ray point sources in the region of interest that are not part of the LAT second source catalog (2FGL), but these point sources are found to be above the standard detection significance threshold when three or more years of LAT data is included.
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http://arxiv.org/abs/1207.6257
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