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http://hdl.handle.net/20.500.12386/34380
Title: | SN 2017gci: a nearby Type I Superluminous Supernova with a bumpy tail | Authors: | Fiore, A. Chen, T. -W. Jerkstrand, A. BENETTI, Stefano CIOLFI, RICCARDO Inserra, C. CAPPELLARO, Enrico PASTORELLO, Andrea 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. |
Issue Date: | 2021 | Journal: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | Number: | 502 | Issue: | 2 | First Page: | 2120 | 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<SUB>g</SUB> = -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 B<SUB>p</SUB> ≃ 6 × 10<SUP>14</SUP> G, an initial period of the magnetar P<SUB>initial</SUB> ≃ 2.8 ms, an ejecta mass $M_{\rm ejecta}\simeq 9\, \mathrm{M}_\odot $ and an ejecta opacity $\kappa \simeq 0.08\, \mathrm{cm}^{2}\, \rm{g}^{-1}$. A CSM-interaction scenario would imply a CSM mass $\simeq 5\, \mathrm{M}_\odot $ and an ejecta mass $\simeq 12\, \mathrm{M}_\odot $. Finally, the nebular spectrum of phase + 187 d was modeled, deriving a mass of $\sim 10\, {\rm M}_\odot$ 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 ($40\, {\rm M}_\odot$) star. | URI: | http://hdl.handle.net/20.500.12386/34380 | URL: | https://academic.oup.com/mnras/article/502/2/2120/6064317 http://arxiv.org/abs/2012.12755v1 |
ISSN: | 0035-8711 | DOI: | 10.1093/mnras/staa4035 | Bibcode ADS: | 2021MNRAS.502.2120F | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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