학술논문
Supernova 2020wnt: An Atypical Superluminous Supernova with a Hidden Central Engine
Document Type
Working Paper
Author
Tinyanont, Samaporn; Woosley, Stan E.; Taggart, Kirsty; Foley, Ryan J.; Yan, Lin; Lunnan, Ragnhild; Davis, Kyle W.; Kilpatrick, Charles D.; Siebert, Matthew R.; Schulze, Steve; Ashall, Chris; Chen, Ting-Wan; De, Kishalay; Dimitriadis, Georgios; Dong, Dillon Z.; Fremling, Christoffer; Gagliano, Alexander; Jha, Saurabh W.; Jones, David O.; Kasliwal, Mansi M.; Miao, Hao-Yu; Pan, Yen-Chen; Perley, Daniel A.; Ravi, Vikram; Rojas-Bravo, César; Sfaradi, Itai; Sollerman, Jesper; Alarcon, Vanessa; Angulo, Rodrigo; Clever, Karoli E.; Crawford, Payton; Couch, Cirilla; Dandu, Srujan; Dhara, Atirath; Johnson, Jessica; Lai, Zhisen; Smith, Carli
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Subject
Language
Abstract
We present observations of a peculiar hydrogen- and helium-poor stripped-envelope (SE) supernova (SN) 2020wnt, primarily in the optical and near-infrared (near-IR). Its peak absolute bolometric magnitude of -20.9 mag and a rise time of 69~days are reminiscent of hydrogen-poor superluminous SNe (SLSNe~I), luminous transients potentially powered by spinning-down magnetars. Before the main peak, there is a brief peak lasting <10 days post-explosion, likely caused by interaction with circumstellar medium (CSM) ejected ~years before the SN explosion. The optical spectra near peak lack a hot continuum and OII absorptions, which are signs of heating from a central engine; they quantitatively resemble those of radioactivity-powered H/He-poor Type Ic SESNe. At ~1 year after peak, nebular spectra reveal a blue pseudo-continuum and narrow OI recombination lines associated with magnetar heating. Radio observations rule out strong CSM interactions as the dominant energy source at +266 days post peak. Near-IR observations at +200-300 day reveal carbon monoxide and dust formation, which causes a dramatic optical light curve dip. Pair-instability explosion models predict slow light curve and spectral features incompatible with observations. SN 2020wnt is best explained as a magnetar-powered core-collapse explosion of a 28 Msun pre-SN star. The explosion kinetic energy is significantly larger than the magnetar energy at peak, effectively concealing the magnetar-heated inner ejecta until well after peak. SN 2020wnt falls into a continuum between normal SNe Ic and SLSNe I and demonstrates that optical spectra at peak alone cannot rule out the presence of a central engine.
Comment: Submitted to ApJ
Comment: Submitted to ApJ