Simultaneous XMM-Newton and ESO VLT observations of SN 1995N: is the wind/ejecta interaction quenching? ?

We present the results of the first XMM-Newton observation of the interacting type IIn supernova 1995N, performed in July 2003. We find that the 0.2‐10.0 keV unabsorbed flux dropped at a value of ’ 1.8 ◊ 10 13 erg cm 2 s 1 , about one order of magnitude lower than that of a previous ASCA observation of January 1998. From all the available X-ray measurements, an interesting scenario emerges where a two-phase (clumpy/smooth) CSM contributes to the X-ray emission. The X-ray spectral analysis shows statistically significant evidence for the presence of two distinct components, that can be modeled with emission from optically thin, thermal plasmas at dierent temperatures. The exponent of the ejecta density distribution inferred from these temperatures is n ’ 6.4. From the fluxes of the two spectral components we derive an estimate of the mass loss rate of the supernova progenitor, ˙ M 10 6 10 4 M yr 1 , consistent with the typical winds of red super-giants. Coordinated optical and infrared observations allow us to reconstruct the simultaneous infrared to X-ray flux distribution of SN 1995N. We find that, at 9 years after explosion, the total energy output is dominated by the direct X-ray thermal emission due to the wind/ejecta interaction, whereas reprocessed optical and near infrared emission contribute to 15% of the X-ray flux.