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SN 2020wnt: a slow-evolving carbon-rich superluminous supernova with no O II lines and a bumpy light curve

Gutiérrez, CP, Pastorello, A, Bersten, M, Benetti, S, Orellana, M, Fiore, A, Karamehmetoglu, E, Kravtsov, T, Reguitti, A, Reynolds, TM, Valerin, G, Mazzali, P, Sullivan, M, Cai, YZ, Elias-Rosa, N, Fraser, M, Hsiao, EY, Kankare, E, Kotak, R, Kuncarayakti, H , Li, Z, Mattila, S, Mo, J, Moran, S, Ochner, P, Shahbandeh, M, Tomasella, L, Wang, X, Yan, S, Zhang, J, Zhang, T and Stritzinger, MD (2022) SN 2020wnt: a slow-evolving carbon-rich superluminous supernova with no O II lines and a bumpy light curve. Monthly Notices of the Royal Astronomical Society, 517 (2). pp. 2056-2075. ISSN 0035-8711

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We present the analysis of SN 2020wnt, an unusual hydrogen-poor superluminous supernova (SLSN-I), at a redshift of 0.032. The light curves of SN 2020wnt are characterized by an early bump lasting ∼5 d, followed by a bright main peak. The SN reaches a peak absolute magnitude of Mmaxr = −20.52 ± 0.03 mag at ∼77.5 d from explosion. This magnitude is at the lower end of the luminosity distribution of SLSNe-I, but the rise-time is one of the longest reported to date. Unlike other SLSNe-I, the spectra of SN 2020wnt do not show O II, but strong lines of C II and Si II are detected. Spectroscopically, SN 2020wnt resembles the Type Ic SN 2007gr, but its evolution is significantly slower. Comparing the bolometric light curve to hydrodynamical models, we find that SN 2020wnt luminosity can be explained by radioactive powering. The progenitor of SN 2020wnt is likely a massive and extended star with a pre-SN mass of 80 M☉ and a pre-SN radius of 15 R☉ that experiences a very energetic explosion of 45 × 1051 erg, producing 4 M☉ of 56Ni. In this framework, the first peak results from a post-shock cooling phase for an extended progenitor, and the luminous main peak is due to a large nickel production. These characteristics are compatible with the pair-instability SN scenario. We note, however, that a significant contribution of interaction with circumstellar material cannot be ruled out.

Item Type: Article
Uncontrolled Keywords: 0201 Astronomical and Space Sciences; Astronomy & Astrophysics
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press (OUP)
SWORD Depositor: A Symplectic
Date Deposited: 20 Mar 2023 10:48
Last Modified: 20 Mar 2023 10:48
DOI or ID number: 10.1093/mnras/stac2747
URI: https://researchonline.ljmu.ac.uk/id/eprint/19132
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