XMM-Newton and Swift observations of the Type IIb SN 2011dh in Messier   51
  The Type IIb SN 2011dh exploded in the nearby galaxy M51 (the Whirlpool Galaxy) and provides us with one of the best laboratory to study early high energy emission from SNe. We give here a comprehensive view of the X-ray properties of SN 2011dh from the analyses of two pointed XMM-Newton early observations as well as of the full Swift X-ray Telescope (XRT) dataset (163 ks). Due to the high XMM-Newton throughput, we were able to satisfactorily fit the X-ray spectrum with two hot diffuse gas components including an additional absorption component to our Galaxy. A power law model provided a worse description of the data. In addition, the early Swift XRT light curve hints of a flux excess at early times (< 3 d), consistent with the adiabatic cooling of stellar's photosphere a few days after the shock breakout. 
Sergio Campana (INAF-OA Brera), Stefan Immler (NASA/GSFC & Univ. of   Maryland)
astro-ph.HE