Strong Evidence against a Non-degenerate Companion in SN 2012cg

• Published in: The Astrophysical journal Vol. 855; no. 1; pp. 6 - 15
• Main Authors: Shappee, B. J., Piro, A. L., Stanek, K. Z., Patel, S. G., Margutti, R. A., Lipunov, V. M., Pogge, R. W.
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 01-03-2018; IOP Publishing
• Subjects: Astrophysics; Light curve; Overflow; Supernovae; supernovae: individual (SN 2012cg)
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/aaa1e9

Even though SN 2012cg is one of the best-studied Type Ia supernovae to date, the nature of its progenitor system has been debated in numerous studies. Specifically, it is difficult to reconcile recent claims of the detection of a ∼6 MS companion with recent deep, late-time flux limits. In this study we add three new constraints. (1) We analyze a new high-signal-to-noise, nebular-phase, Large Binocular Telescope/MODS spectrum of SN 2012cg and place an upper limit on the amount of low-velocity, solar-abundance material removed from a possible companion of . (2) We use Swift X-ray observations to constrain the pre-explosion mass-loss rate to be for . (3) We carefully reanalyze a prediscovery MASTER image, and with published light curves of SN 2012cg we estimate the time of first light and conservatively constrain the radius of a Roche-lobe overflowing companion to be . These observations disagree with a large nearby companion, and when considered with other studies of SN 2012cg's progenitor system, essentially rule out a non-degenerate companion.