Fast and Not-so-Furious: Case Study of the Fast and Faint Type IIb SN 2021bxu
| Autor: | Desai, Dhvanil D., Ashall, Chris, Shappee, Benjamin J., Morrell, Nidia, Galbany, Lluís, Burns, Christopher R., DerKacy, James M., Hinkle, Jason T., Hsiao, Eric, Kumar, Sahana, Lu, Jing, Phillips, Mark M., Shahbandeh, Melissa, Stritzinger, Maximilian D., Baron, Eddie, Bersten, Melina C., Brown, Peter J., de Jaeger, Thomas, Elias-Rosa, Nancy, Folatelli, Gastón, Huber, Mark E., Mazzali, Paolo, Müller-Bravo, Tomás E., Piro, Anthony L., Polin, Abigail, Suntzeff, Nicholas B., Anderson, Joseph P., Chambers, Kenneth C., Chen, Ting-Wan, de Boer, Thomas, Fulton, Michael D., Gao, Hua, Gromadzki, Mariusz, Inserra, Cosimo, Magnier, Eugene A., Nicholl, Matt, Ragosta, Fabio, Wainscoat, Richard, Young, David R. |
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| Rok vydání: | 2023 |
| Předmět: | |
| DOI: | 10.48550/arxiv.2303.13581 |
| Popis: | We present photometric and spectroscopic observations and analysis of SN 2021bxu (ATLAS21dov), a low-luminosity, fast-evolving Type IIb supernova (SN). SN 2021bxu is unique, showing a large initial decline in brightness followed by a short plateau phase. With $M_r = -15.93 \pm 0.16\, \mathrm{mag}$ during the plateau, it is at the lower end of the luminosity distribution of stripped-envelope supernovae (SE-SNe) and shows a distinct $\sim$10 day plateau not caused by H- or He-recombination. SN 2021bxu shows line velocities which are at least $\sim1500\,\mathrm{km\,s^{-1}}$ slower than typical SE-SNe. It is photometrically and spectroscopically similar to Type IIb SNe during the photospheric phases of evolution, with similarities to Ca-rich IIb SNe. We find that the bolometric light curve is best described by a composite model of shock interaction between the ejecta and an envelope of extended material, combined with a typical SN IIb powered by the radioactive decay of $^{56}$Ni. The best-fit parameters for SN 2021bxu include a $^{56}$Ni mass of $M_{\mathrm{Ni}} = 0.029^{+0.004}_{-0.005}\,\mathrm{M_{\odot}}$, an ejecta mass of $M_{\mathrm{ej}} = 0.61^{+0.06}_{-0.05}\,\mathrm{M_{\odot}}$, and an ejecta kinetic energy of $K_{\mathrm{ej}} = 8.8^{+1.1}_{-1.0} \times 10^{49}\, \mathrm{erg}$. From the fits to the properties of the extended material of Ca-rich IIb SNe we find a trend of decreasing envelope radius with increasing envelope mass. SN 2021bxu has $M_{\mathrm{Ni}}$ on the low end compared to SE-SNe and Ca-rich SNe in the literature, demonstrating that SN 2021bxu-like events are rare explosions in extreme areas of parameter space. The progenitor of SN 2021bxu is likely a low mass He star with an extended envelope. Comment: 18 pages, 15 figures, accepted to MNRAS |
| Databáze: | OpenAIRE |
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