Astrophys. J., 882, 68-68 (2019/September-1)
Observational signature of circumstellar interaction and 56Ni-mixing in the Type II Supernova 2016gfy.
SINGH A., KUMAR B., MORIYA T.J., ANUPAMA G.C., SAHU D.K., BROWN P.J., ANDREWS J.E. and SMITH N.
Abstract (from CDS):
The optical and ultraviolet broadband photometric and spectroscopic observations of the Type II supernova (SN) 2016gfy are presented. The V-band light curve (LC) shows a distinct plateau phase with a slope of s2 ∼ 0.12 mag (100 day)–1 and a duration of 90 ± 5 days. Detailed analysis of SN 2016gfy provided a mean 56Ni mass of 0.033 ± 0.003 M☉, a progenitor radius of ∼350-700 R☉, a progenitor mass of ∼12-15 M☉, and an explosion energy of (0.9-1.4) x 1051 erg s–1. The P-Cygni profile of Hα in the early-phase spectra (∼11-21 days) shows a boxy emission. Assuming that this profile arises from the interaction of the SN ejecta with the pre-existing circumstellar material (CSM), it is inferred that the progenitor underwent a recent episode (30-80 yr prior to the explosion) of enhanced mass loss. Numerical modeling suggests that the early LC peak is reproduced better with an existing CSM of 0.15 M☉ spread out to ∼70 au. A late-plateau bump is seen in the VRI LCs during ∼50-95 days. This bump is explained as a result of the CSM interaction and/or partial mixing of radioactive 56Ni in the SN ejecta. Using strong-line diagnostics, a subsolar oxygen abundance is estimated for the supernova H II region (12 + log(O/H) = 8.50 ± 0.11), indicating an average metallicity for the host of an SN II. A star formation rate of ∼8.5 M☉ yr–1 is estimated for NGC 2276 using the archival GALEX FUV data.
© 2019. The American Astronomical Society. All rights reserved.
galaxies: individual: NGC 2276 - supernovae: general - supernovae: individual: SN 2016gfy
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