The Most Rapidly Declining Type I Supernova 2019bkc/ATLAS19dqr
: Ping Chen, Subo Dong, M. D. Stritzinger, Simon Holmbo, Jay Strader, C. S. Kochanek, Eric W. Peng, S. Benetti, D. Bersier, Sasha Brownsberger, David A. H. Buckley, Mariusz Gromadzki, Shane Moran, A. Pastorello, Elias Aydi, Subhash Bose, Thomas Connor, K. Boutsia, F. Di Mille, N. Elias-Rosa, K. Decker French, Thomas W.-S. Holoien, Seppo Mattila, B. J. Shappee, Antony A. Stark, Samuel J. Swihart
Publisher: IOP PUBLISHING LTD
: 2020
: Astrophysical Journal Letters
: ASTROPHYSICAL JOURNAL LETTERS
: ASTROPHYS J LETT
: ARTN L6
: 889
: 1
: 17
: 2041-8205
DOI: https://doi.org/10.3847/2041-8213/ab62a4
: https://research.utu.fi/converis/portal/detail/Publication/46861022
We report observations of the hydrogen-deficient supernova (SN) 2019bkc/ATLAS19dqr. With B- and r-band decline between peak and 10 days post peak of Dm10 (B) = 5.24. 0.07 mag and Dm10 (r) = 3.85. 0.10 mag, respectively, SN.2019bkc is the most rapidly declining SN I discovered so far. While its closest matches are the rapidly declining SN.2005ek and SN. 2010X, the light curves and spectra of SN.2019bkc show some unprecedented characteristics. SN.2019bkc appears "hostless," with no identifiable host galaxy near its location, although it may be associated with the galaxy cluster MKW1 at z.=.0.02. We evaluate a number of existing models of fast-evolving SNe, and we find that none of them can satisfactorily explain all aspects of SN.2019bkc observations.