SN 2017gci: A nearby Type i Superluminous Supernova with a bumpy tail
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2021-04-01
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Mcode
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Language
en
Pages
20
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Monthly Notices of the Royal Astronomical Society, Volume 502, issue 2, pp. 2120-2139
Abstract
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.Description
Publisher Copyright: © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.
Keywords
supernova: general, supernovae: individual: SN 2017gci, Transients: supernovae
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Citation
Fiore, A, Chen, T W, Jerkstrand, A, Benetti, S, Ciolfi, R, Inserra, C, Cappellaro, E, Pastorello, A, Leloudas, G, Schulze, S, Berton, M, Burke, J, McCully, C, Fong, W, Galbany, L, Gromadzki, M, Gutiérrez, C P, Hiramatsu, D, Hosseinzadeh, G, Howell, D A, Kankare, E, Lunnan, R, Müller-Bravo, T E, O' Neill, D, Nicholl, M, Rau, A, Sollerman, J, Terreran, G, Valenti, S & Young, D R 2021, ' SN 2017gci: A nearby Type i Superluminous Supernova with a bumpy tail ', Monthly Notices of the Royal Astronomical Society, vol. 502, no. 2, pp. 2120-2139 . https://doi.org/10.1093/mnras/staa4035