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arXiv · 2111.09470

Discovery of the Fastest Early Optical Emission from Overluminous SN Ia 2020hvf: A Thermonuclear Explosion within a Dense Circumstellar Environment

Ji-an Jiang·Keiichi Maeda·Miho Kawabata·Mamoru Doi·Toshikazu Shigeyama·Masaomi Tanaka·Nozomu Tominaga·Ken'ichi Nomoto·Yuu Niino·Shigeyuki Sako·Ryou Ohsawa·Malte Schramm·Masayuki Yamanaka·Naoto Kobayashi·Hidenori Takahashi·Tatsuya Nakaoka·Koji S. Kawabata·Keisuke Isogai·Tsutomu Aoki·Sohei Kondo·Yuki Mori·Ko Arimatsu·Toshihiro Kasuga·Shin-ichiro Okumura·Seitaro Urakawa·Daniel E. Reichart·Kenta Taguchi·Noriaki Arima·Jin Beniyama·Kohki Uno·Taisei Hamada
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Abstract

In this Letter we report a discovery of a prominent flash of a peculiar overluminous Type Ia supernova, SN 2020hvf, in about 5 hours of the supernova explosion by the first wide-field mosaic CMOS sensor imager, the Tomo-e Gozen Camera. The fast evolution of the early flash was captured by intensive intranight observations via the Tomo-e Gozen high-cadence survey. Numerical simulations show that such a prominent and fast early emission is most likely generated from an interaction between $0.01~M_{\odot}$ circumstellar material (CSM) extending to a distance of $\sim$$10^{13}~\text{cm}$ and supernova ejecta soon after the explosion, indicating a confined dense CSM formation at the final evolution stage of the progenitor of SN 2020hvf. Based on the CSM-ejecta interaction-induced early flash, the overluminous light curve, and the high ejecta velocity of SN 2020hvf, we suggest that the SN 2020hvf may originate from a thermonuclear explosion of a super-Chandrasekhar-mass white dwarf ("super-$M\rm_{Ch}$ WD"). Systematical investigations on explosion mechanisms and hydrodynamic simulations of the super-$M\rm_{Ch}$ WD explosion are required to further test the suggested scenario and understand the progenitor of this peculiar supernova.

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Ji-an Jiang, Keiichi Maeda, Miho Kawabata, Mamoru Doi, Toshikazu Shigeyama, Masaomi Tanaka, Nozomu Tominaga, Ken'ichi Nomoto, Yuu Niino, Shigeyuki Sako, Ryou Ohsawa, Malte Schramm, Masayuki Yamanaka, Naoto Kobayashi, Hidenori Takahashi, Tatsuya Nakaoka, Koji S. Kawabata, Keisuke Isogai, Tsutomu Aoki, Sohei Kondo, Yuki Mori, Ko Arimatsu, Toshihiro Kasuga, Shin-ichiro Okumura, Seitaro Urakawa, Daniel E. Reichart, Kenta Taguchi, Noriaki Arima, Jin Beniyama, Kohki Uno, Taisei Hamada. 2021-11-18. Discovery of the Fastest Early Optical Emission from Overluminous SN Ia 2020hvf: A Thermonuclear Explosion within a Dense Circumstellar Environment. https://doi.org/10.3847/2041-8213%2Fac375f

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