SN 2017gci: a nearby Type I Superluminous Supernova with a bumpy tail
Lunnan R; Gromadzki M; Young DR; Jerkstrand A; Fong W; Kankare E; Pastorello A; Chen TW; Burke J; Hosseinzadeh G; Valenti S; Schulze S; Howell DA; McCully C; Muller-Bravo TE; Berton M; Inserra C; Leloudas G; Galbany L; Benetti S; Ciolfi R; Cappellaro E; Sollerman J; O' Neill D; Fiore A; Terreran G; Rau A; Nicholl M; Hiramatsu D; Gutierrez CP
SN 2017gci: a nearby Type I Superluminous Supernova with a bumpy tail
Lunnan R
Gromadzki M
Young DR
Jerkstrand A
Fong W
Kankare E
Pastorello A
Chen TW
Burke J
Hosseinzadeh G
Valenti S
Schulze S
Howell DA
McCully C
Muller-Bravo TE
Berton M
Inserra C
Leloudas G
Galbany L
Benetti S
Ciolfi R
Cappellaro E
Sollerman J
O' Neill D
Fiore A
Terreran G
Rau A
Nicholl M
Hiramatsu D
Gutierrez CP
OXFORD UNIV PRESS
Julkaisun pysyvä osoite on:
https://urn.fi/URN:NBN:fi-fe2021093048210
https://urn.fi/URN:NBN:fi-fe2021093048210
Tiivistelmä
We 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 M-g = -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 angstrom after similar to 51 d from the maximum light, which is followed by a sharp knee in the LC. If we interpret this feature as H alpha, 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 B-p similar or equal to 6 x 10(14) G, an initial period of the magnetar P-initial similar or equal to 2.8 ms, an ejecta mass M-ejecta similar or equal to 9M(circle dot) and an ejecta opacity kappa similar or equal to 0.08 cm(2) g(-1). A CSM-interaction scenario would imply a CSM mass similar or equal to 5 M-circle dot and an ejecta mass similar or equal to 12M(circle dot). Finally, the nebular spectrum of phase + 187 d was modeled, deriving a mass of similar or equal to 10 M-circle dot 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 (40 M-circle dot) star.
Kokoelmat
- Rinnakkaistallenteet [19207]