On the nature of the circumstellar medium of the remarkable type Ia/IIn supernova, SN 2002ic

Abstract

We present results from the first high resolution, high S/N, spectrum of SN 2002ic. The resolved Halpha line has a P Cygni-type profile, clearly demonstrating the presence of a dense, slow-moving (100 km/s) outflow. We have additionally found a huge near-IR excess, hitherto unseen in type Ia SNe. We argue that this is due to an IR light-echo arising from the pre-existing dusty circumstellar medium. We deduce a CSM mass probably exceeding 0.3Msun produced by a mass loss rate greater than several times 10^-4 Msun/yr. For the progenitor, we favour a single degenerate system where the companion is a post-AGB star. As a by-product of our optical data, we are able to provide a firm identification of the host galaxy of SN 2002ic.