Discovery of 0.5 MK Gas in the Center of the Virgo Cluster

Abstract

An observation of M87, the central galaxy of the Virgo Cluster, was performed by the deep survey telescope aboard the Extreme-Ultraviolet Explorer, in the 0.065-0.245 keV energy band. A point source and an extended emission halo of radius ~20' are clearly visible in the data, and represent the first detection of cluster gas emission in the EUV. The emission cannot be explained by the well-known cluster gas at X-ray temperatures. Instead, it is necessary to introduce a second gas component, with temperature between 5 × 105 and 106 K. The rapid cooling of plasmas at such temperatures implies a mass accretion rate of more than 300 M☉ yr-1. It is unlikely that the phenomenon is directly related to a cooling flow, which involves a much lower accretion rate of ~10 M☉ yr-1.