Chandra’s Tryst with SN 1995N

Abstract

We present the spectroscopic and imaging analysis of Type IIn supernova SN 1995N observed with the Chandra X-Ray Observatory on 2004 March 27. We compare the spectrum obtained from our Chandra observation with that of the previous observation with ASCA in 1998. We find the presence of neon lines in the Chandra spectrum that were not reported in the ASCA observation. We see no evidence of iron in either epoch. The observed absorption column depth indicates an extra component over and above the Galactic absorption component and is possibly due to a cool dense shell between the reverse shock and the contact discontinuity in the ejecta. The ASCA and the ROSAT observations suggested a nonlinear behavior of the X-ray light curve. However, with the higher spatial resolution and sensitivity of Chandra, we separate out many nearby sources in the supernova field of view that had additionally contributed to the supernova flux due to the large point-spread function of ASCA. Taking out the contribution of those nearby sources, we find that the light curves are consistent with a linear decline profile. We consider the light curve in the high-energy band separately. We discuss our results in the context of models of nucleosynthesis and the interaction of the shock waves with the circumstellar medium in core-collapse supernovae.