Late-time photometry of Type Ia Supernova SN 2012cg reveals the radioactive decay of 57Co

Or Graur*, David Zurek, Michael M. Shara, Adam G. Riess, Ivo R. Seitenzahl, Armin Rest

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Downloads (Pure)

Abstract

Seitenzahl et al. (2009) have predicted that roughly three years after its explosion, the light we receive from a Type Ia supernova (SN Ia) will come mostly from reprocessing of electrons and X-rays emitted by the radioactive decay chain 57Co --> 57Fe, instead of positrons from the decay chain 56Co --> 56Fe that dominates the SN light at earlier times. Using the Hubble Space Telescope, we followed the light curve of the SN Ia SN 2012cg out to 1055 days after maximum light. Our measurements are consistent with the light curves predicted by the contribution of energy from the reprocessing of electrons and X-rays emitted by the decay of 57Co, offering evidence that 57Co is produced in SN Ia explosions. However, the data are also consistent with a light echo ~14 mag fainter than SN 2012cg at peak. Assuming no light-echo contamination, the mass ratio of 57Ni and 56Ni produced by the explosion, a strong constraint on any SN Ia explosion model, is 0.043 +0.012 -0.011, roughly twice Solar. In the context of current explosion models, this value favors a progenitor white dwarf with a mass near the Chandrasekhar limit.
Original languageEnglish
Article number31
JournalThe Astrophysical Journal
Volume819
DOIs
Publication statusPublished - 1 Mar 2016
Externally publishedYes

Keywords

  • SN_HIGHLIGHT

Fingerprint

Dive into the research topics of 'Late-time photometry of Type Ia Supernova SN 2012cg reveals the radioactive decay of 57Co'. Together they form a unique fingerprint.

Cite this