Journal article · Preprint article
SN 2017gci: a nearby Type I Superluminous Supernova with a bumpy tail
National Institute for Astrophysics1
Northwestern University2
Universidad De Granada3
University of Warsaw4
University of Southampton5
Harvard-Smithsonian Center for Astrophysics6
Queen's University Belfast7
University of Birmingham8
Max Planck Institute for Extraterrestrial Physics9
University of California at San Diego10
Stockholm University11
Cardiff University12
Astrophysics and Atmospheric Physics, National Space Institute, Technical University of Denmark13
National Space Institute, Technical University of Denmark14
Weizmann Institute of Science15
University of Turku16
University of California at Santa Barbara17
Las Cumbres Observatory Global Telescope Network, Inc.18
...and 8 moreWe present and discuss the optical spectrophotometric observations of the nearby (z = 0.087) Type I superluminous supernova (SLSN I) SN 2017gci, whose peak K-corrected absolute magnitude reaches Mg = −21.5 mag. Its photometric and spectroscopic evolution includes features of both slow- and of fast-evolving SLSN I, thus favoring a continuum distribution between the two SLSN-I subclasses.
In particular, similarly to other SLSNe I, the multiband light curves (LCs) of SN 2017gci show two re-brightenings at about 103 and 142 d after the maximum light. Interestingly, this broadly agrees with a broad emission feature emerging around 6520 Å after ∼51 d from the maximum light, which is followed by a sharp knee in the LC.
If we interpret this feature as Hα, this could support the fact that the bumps are the signature of late interactions of the ejecta with a (hydrogen-rich) circumstellar material. Then we fitted magnetar- and CSM-interaction-powered synthetic LCs on to the bolometric one of SN 2017gci. In the magnetar case, the fit suggests a polar magnetic field Bp ≃ 6 × 1014 G, an initial period of the magnetar Pinitial ≃ 2.8 ms, an ejecta mass Mejecta≃9M⊙ and an ejecta opacity κ≃0.08cm2g−1.
A CSM-interaction scenario would imply a CSM mass ≃5M⊙ and an ejecta mass ≃12M⊙. Finally, the nebular spectrum of phase + 187 d was modeled, deriving a mass of ∼10M⊙ for the ejecta. Our models suggest that either a magnetar or CSM interaction might be the power sources for SN 2017gci and that its progenitor was a massive (40M⊙) star.
Language: | English |
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Year: | 2021 |
Pages: | 2120-2139 |
ISSN: | 13652966 , 00358711 and 13658711 |
Types: | Journal article and Preprint article |
DOI: | 10.1093/mnras/staa4035 |
ORCIDs: | Leloudas, G. , 0000-0002-0403-3331 , 0000-0002-3256-0016 , 0000-0003-3140-8933 , 0000-0002-3968-4409 , 0000-0001-6797-1889 , 0000-0002-1058-9109 , 0000-0002-1296-6887 , 0000-0003-2375-2064 and 0000-0003-3939-7167 |