Abstract
We present near-infrared (NIR) and optical observations of the Type Ic supernova (SN Ic) SN 2021krf obtained between days 13 and 259 at several ground-based telescopes. The NIR spectrum at day 68 exhibits a rising K-band continuum flux density longward of ∼2.0 μm, and a late-time optical spectrum at day 259 shows strong [O i] 6300 and 6364 Å emission-line asymmetry, both indicating the presence of dust, likely formed in the SN ejecta. We estimate a carbon-grain dust mass of ∼2 × 10−5 M ⊙ and a dust temperature of ∼900-1200 K associated with this rising continuum and suggest the dust has formed in SN ejecta. Utilizing the one-dimensional multigroup radiation-hydrodynamics code STELLA, we present two degenerate progenitor solutions for SN 2021krf, characterized by C-O star masses of 3.93 and 5.74 M ⊙, but with the same best-fit 56Ni mass of 0.11 M ⊙ for early times (0-70 days). At late times (70-300 days), optical light curves of SN 2021krf decline substantially more slowly than those expected from 56Co radioactive decay. Lack of H and He lines in the late-time SN spectrum suggests the absence of significant interaction of the ejecta with the circumstellar medium. We reproduce the entire bolometric light curve with a combination of radioactive decay and an additional powering source in the form of a central engine of a millisecond pulsar with a magnetic field smaller than that of a typical magnetar.
Original language | English (US) |
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Article number | 14 |
Journal | Astrophysical Journal |
Volume | 950 |
Issue number | 1 |
DOIs | |
State | Published - Jun 1 2023 |
Funding
We thank the anonymous referee for helpful comments that improved this manuscript. We are grateful to Matt Nicholl for his insightful discussions on generating bolometric luminosity, and Griffin Hosseinzadeh for his help with the LCO photometry pipeline setup. We thank Maria Niculescu-Duvaz and Roger Wesson for their help with setting up DAMOCLES. This research is based in part on observations obtained at the international Gemini Observatory, a program of NSF's NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation (NSF), on behalf of the Gemini Observatory partnership: the NSF (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). A.P.R. and J.R. are in part supported by the NASA ADAP grant (80NSSC20K0449) for the study of SN dust. S.C.Y. and S.H.P. are supported by the National Research Foundation of Korea (NRF) grant (NRF-2019R1A2C2010885). Gemini telescope time is partly awarded by K-GMT of the Korea Astronomy and Space Science Institute (KASI). This work makes use of observations from the Las Cumbres Observatory global telescope network. The LCO team is supported by NSF grants AST-1911225 and AST-1911151. Research by S.V. and Y.D. is supported by NSF grant AST-2008108. R.K.T. is supported by the ÚNKP-22-4 New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund, and the NKFIH/OTKA FK-134432 grant of the National Research, Development and Innovation (NRDI) Office of Hungary. S.B. is supported by grant RSF 19-12-00229 for the development of STELLA code and by RFBR 21-52-12032 in the studies of SNIc. A.V.F. is grateful for financial support from the Christopher R. Redlich Fund and numerous individual donors. The UCSC team is supported in part by the Gordon & Betty Moore Foundation, the Heising-Simons Foundation, and by a fellowship from the David and Lucile Packard Foundation to R.J.F. A major upgrade of the Kast spectrograph on the Shane 3 m telescope at Lick Observatory was made possible through generous gifts from the Heising-Simons Foundation as well as William and Marina Kast. Research at Lick Observatory is partially supported by a generous gift from Google. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA; the observatory was made possible by the generous financial support of the W. M. Keck Foundation.
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science