分类： 天文学 >> 天文学 提交时间： 2023-02-19
Aravind P. Ravi
Jeonghee Rho
Sangwook Park
Seong Hyun Park
Sung-Chul Yoon
T. R. Geballe
Jozsef Vinko
Samaporn Tinyanont
K. Azalee Bostroem
Jamison Burke
Daichi Hiramatsu
D. Andrew Howell
Curtis McCully
Megan Newsome
Estefania Padilla Gonzalez
Craig Pellegrino
Regis Cartier
Tyler Pritchard
Morten Andersen
Sergey Blinnikov
摘要： 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 $\sim 2.0 \mu$m, which is likely from freshly formed dust in the SN ejecta. We estimate a carbon-grain dust mass of $\sim 2 \times 10^{-5}$ M$_{\odot}$ and a dust temperature of $\sim 900-1200$ 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$_{\odot}$, but with the same best-fit $^{56}$Ni mass of 0.11 M$_{\odot}$ for early times (0-70 days). At late times (70-300 days), optical light curves of SN 2021krf decline substantially more slowly than that expected from $^{56}$Co radioactive decay. A late-time optical spectrum on day 259 shows strong Ca II and [O I] ejecta lines from the SN. 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.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Marc Williamson
Christian Vogl
Maryam Modjaz
Wolfgang Kerzendorf
Jaladh Singhal
Teresa Boland
Jamison Burke
Zhihao Chen
Daichi Hiramatsu
Lluis Galbany
Estefania Padilla Gonzalez
D. Andrew Howell
Saurabh W. Jha
Lindsey A. Kwok
Curtis McCully
Megan Newsome
Craig Pellegrino
Jeonghee Rho
Giacomo Terreran
Xiaofeng Wang
摘要： With the advent of high cadence, all-sky automated surveys, supernovae (SNe) are now discovered closer than ever to their dates of explosion. However, young pre-maximum light follow-up spectra of Type Ic supernovae (SNe Ic), probably arising from the most stripped massive stars, remain rare despite their importance. In this paper we present a set of 49 optical spectra observed with the Las Cumbres Observatory through the Global Supernova Project for 6 SNe Ic, including a total of 17 pre-maximum spectra, of which 8 are observed more than a week before V-band maximum light. This dataset increases the total number of publicly available pre-maximum light SN Ic spectra by 25% and we provide publicly available SNID templates that will significantly aid in the fast identification of young SNe Ic in the future. We present detailed analysis of these spectra, including Fe II 5169 velocity measurements, O I 7774 line strengths, and continuum shapes. We compare our results to published samples of stripped supernovae in the literature and find one SN in our sample that stands out. SN 2019ewu has a unique combination of features for a SN Ic: an extremely blue continuum, high absorption velocities, a P-cygni shaped feature almost 2 weeks before maximum light that TARDIS radiative transfer modeling attributes to C II rather than H$\alpha$, and weak or non-existent O I 7774 absorption feature until maximum light.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Sam Geen
Poojan Agrawal
Paul A. Crowther
B. W. Keller
Alex de Koter
Zsolt Keszthelyi
Freeke van de Voort
Ahmad A. Ali
Frank Backs
Lars Bonne
Vittoria Brugaletta
Annelotte Derkink
Sylvia Ekström
Yvonne A. Fichtner
Luca Grassitelli
Ylva Götberg
Erin R. Higgins
Eva Laplace
Kong You Liow
Marta Lorenzo
摘要： Stars strongly impact their environment, and shape structures on all scales throughout the universe, in a process known as ``feedback''. Due to the complexity of both stellar evolution and the physics of larger astrophysical structures, there remain many unanswered questions about how feedback operates, and what we can learn about stars by studying their imprint on the wider universe. In this white paper, we summarize discussions from the Lorentz Center meeting `Bringing Stellar Evolution and Feedback Together' in April 2022, and identify key areas where further dialogue can bring about radical changes in how we view the relationship between stars and the universe they live in.
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