On SN 2003fg: The Probable Super-Chandrasekhar-Mass SN Ia

Abstract

Howell et al. have reported the discovery of SN Ia SN 2003fg (SNLS-03D3bb) and conclude that SN 2003fg is very likely a super-Chandrasekhar-mass SN Ia perhaps with a mass of order 2 solar masses. Their work is the first strong evidence that has been presented for a super-Chandrasekhar SN Ia. We have performed an analysis of the SN 2003fg data using the Yoon & Langer binding energy formula for a rotating super-Chandrasekhar-mass white dwarf (also used by Howell et al.) included in a simple model of SNe Ia (which we call the SSC model for Simple Super-Chandrasekhar model for SNe Ia) which assumes spherically symmetric ejecta and relies on the approximations of an exponential density profile for SN Ia ejecta and of a sharp boundary of the SN Ia iron-peak-element core. Our results support the conclusion of Howell et al.: SN 2003fg is very probably super-Chandrasekhar and probably has mass of order 2 solar masses.