2002ApJ...573L..27I

We present two high-resolution Chandra X-ray observations of supernova (SN) 1994I that show, for the first time, that the interaction of the blast wave from a Type Ic SN with its surrounding circumstellar material (CSM) can give rise to soft X-ray emission. Given a 0.3-2 keV band X-ray luminosity of L_X∼1x10³⁷ ergs.s^–1 between 6 and 7 years after the outburst of SN 1994I, and assuming the X-ray emission arises from the shock-heated CSM, we derive a pre-SN mass-loss rate of M{dot}∼1x10^–5 M_☉ yr^–1(v_w/10 km.s^–1). Combining the results with earlier ROSAT observations, we construct the X-ray light curve of SN 1994I. A best-fit X-ray rate of decline of L_X∝t^–s, with index s∼1 and a CSM density profile of ρ_csm∝r^–1.9±0.1, is inferred, consistent with what is expected for a constant mass-loss rate and a constant wind velocity profile for the SN progenitor (ρ_csm∝r^–2).