Observational Signature of Circumstellar Interaction and 56Ni-mixing in the Type II Supernova 2016gfy
Moriya, Takashi J.
Anupama, G. C.
Sahu, D. K.
Brown, Peter J.
Andrews, Jennifer E.
AffiliationUniv Arizona, Steward Observ
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationAvinash Singh et al 2019 ApJ 882 68
RightsCopyright © 2019. The American Astronomical Society. All rights reserved.
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AbstractThe 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 s(2) similar to 0.12 mag (100 day)(-1) and a duration of 90 +/- 5 days. Detailed analysis of SN 2016gfy provided a mean Ni-56 mass of 0.033 +/- 0.003 M-circle dot, a progenitor radius of similar to 350-700 R-circle dot, a progenitor mass of similar to 12-15 M-circle dot, and an explosion energy of (0.9-1.4) x 10(51) erg s(-1). The P-Cygni profile of H alpha in the early-phase spectra (similar to 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-circle dot spread out to similar to 70 au. A late-plateau bump is seen in the VRI LCs during similar to 50-95 days. This bump is explained as a result of the CSM interaction and/or partial mixing of radioactive Ni-56 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 similar to 8.5 M-circle dot yr(-1) is estimated for NGC 2276 using the archival GALEX FUV data.
VersionFinal published version
SponsorsScience and Engineering Research Board (SERB) under the Department of Science & Technology (DST), Govt. of India [PDF/2016/001563]; BRICS grant [DST/IMRCD/BRICS/PilotCall1/MuMeSTU/2017(G)]; DST/JSPS grant [DST/INT/JSPS/P/281/2018]