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SN 2020acat: an energetic fast rising Type IIb supernova

Medler, K, Mazzali, PA, Teffs, J, Ashall, C, Anderson, JP, Arcavi, I, Benetti, S, Bostroem, KA, Burke, J, Cai, YZ, Charalampopoulos, P, Elias-Rosa, N, Ergon, M, Galbany, L, Gromadzki, M, Hiramatsu, D, Howell, DA, Inserra, C, Lundqvist, P, McCully, C , Müller-Bravo, T, Newsome, M, Nicholl, M, Gonzalez, EP, Paraskeva, E, Pastorello, A, Pellegrino, C, Pessi, PJ, Reguitti, A, Reynolds, TM, Roy, R, Terreran, G, Tomasella, L and Young, DR (2022) SN 2020acat: an energetic fast rising Type IIb supernova. Monthly Notices of the Royal Astronomical Society, 513 (4). pp. 5540-5558. ISSN 0035-8711

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The ultraviolet (UV) and near-infrared (NIR) photometric and optical spectroscopic observations of SN 2020acat covering ∼250 d after explosion are presented here. Using the fast rising photometric observations, spanning from the UV to NIR wavelengths, a pseudo-bolometric light curve was constructed and compared to several other well-observed Type IIb supernovae (SNe IIb). SN 2020acat displayed a very short rise time reaching a peak luminosity of Log10(L) = 42.49 ± 0.17 erg s-1 in only ∼14.6 ± 0.3 d. From modelling of the pseudo-bolometric light curve, we estimated a total mass of 56Ni synthesized by SN 2020acat of MNi = 0.13 ± 0.03 M⊙, with an ejecta mass of Mej = 2.3 ± 0.4 M⊙ and a kinetic energy of Ek = 1.2 ± 0.3 × 1051 erg. The optical spectra of SN 2020acat display hydrogen signatures well into the transitional period (≳ 100 d), between the photospheric and the nebular phases. The spectra also display a strong feature around 4900 Å that cannot be solely accounted for by the presence of the Fe ii 5018 line. We suggest that the Fe ii feature was augmented by He i 5016 and possibly by the presence of N ii 5005. From both photometric and spectroscopic analysis, we inferred that the progenitor of SN 2020acat was an intermediate-mass compact star with an MZAMS of 15-20 M⊙.

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: 01 Nov 2022 10:32
Last Modified: 01 Nov 2022 10:32
DOI or ID number: 10.1093/mnras/stac1192
URI: https://researchonline.ljmu.ac.uk/id/eprint/17978
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