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SN 2021foa: The "Flip-Flop" Type IIn / Ibn supernova

Fuente: arXiv

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Dettagli Bibliografici
Autori principali:	Farias, D., Gall, C., Narayan, G., Rest, S., Villar, V. A., Angus, C. R., Auchettl, K., Davis, K. W., Foley, R., Gagliano, A., Hjorth, J., Izzo, L., Kilpatrick, C. D., Perkins, H . M. L., Ramirez-Ruiz, E., Ransome, C. L., Sarangi, A., Yarza, R., Coulter, D. A., Jones, D. O., Khetan, N., Rest, A., Siebert, M. R., Swift, J. J., Taggart, K., Tinyanont, S., Wrubel, P., de Boer, T. J. L., Clever, K. E., Dhara, A., Gao, H., Lin, C. -C.
Natura:	Preprint
Pubblicazione:	2024
Soggetti:	High Energy Astrophysical Phenomena
Accesso online:	Acceder al recurso
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_version_	1866913565369171968
author	Farias, D. Gall, C. Narayan, G. Rest, S. Villar, V. A. Angus, C. R. Auchettl, K. Davis, K. W. Foley, R. Gagliano, A. Hjorth, J. Izzo, L. Kilpatrick, C. D. Perkins, H . M. L. Ramirez-Ruiz, E. Ransome, C. L. Sarangi, A. Yarza, R. Coulter, D. A. Jones, D. O. Khetan, N. Rest, A. Siebert, M. R. Swift, J. J. Taggart, K. Tinyanont, S. Wrubel, P. de Boer, T. J. L. Clever, K. E. Dhara, A. Gao, H. Lin, C. -C.
author_facet	Farias, D. Gall, C. Narayan, G. Rest, S. Villar, V. A. Angus, C. R. Auchettl, K. Davis, K. W. Foley, R. Gagliano, A. Hjorth, J. Izzo, L. Kilpatrick, C. D. Perkins, H . M. L. Ramirez-Ruiz, E. Ransome, C. L. Sarangi, A. Yarza, R. Coulter, D. A. Jones, D. O. Khetan, N. Rest, A. Siebert, M. R. Swift, J. J. Taggart, K. Tinyanont, S. Wrubel, P. de Boer, T. J. L. Clever, K. E. Dhara, A. Gao, H. Lin, C. -C.
contents	We present a comprehensive analysis of the photometric and spectroscopic evolution of SN~2021foa, unique among the class of transitional supernovae for repeatedly changing its spectroscopic appearance from hydrogen-to-helium-to-hydrogen-dominated (IIn-to-Ibn-to-IIn) within 50 days past peak brightness. The spectra exhibit multiple narrow ($\approx$ 300--600~km~s$^{-1}$) absorption lines of hydrogen, helium, calcium and iron together with broad helium emission lines with a full-width-at-half-maximum (FWHM) of $\sim 6000$~km~s$^{-1}$. For a steady, wind-mass loss regime, light curve modeling results in an ejecta mass of $\sim 8$ M$_{\odot}$ and CSM mass below 1 M$_{\odot}$, and an ejecta velocity consistent with the FWHM of the broad helium lines. We obtain a mass-loss rate of $\approx 2$ M$_{\odot} {\rm yr}^{-1}$. This mass-loss rate is three orders of magnitude larger than derived for normal Type II SNe. We estimate that the bulk of the CSM of SN~2021foa must have been expelled within half a year, about 15 years ago. Our analysis suggests that SN~2021foa had a helium rich ejecta which swept up a dense shell of hydrogen rich CSM shortly after explosion. At about 60 days past peak brightness, the photosphere recedes through the dense ejecta-CSM region, occulting much of the red-shifted emission of the hydrogen and helium lines, which results in observed blue-shift ($\sim -3000$~km~s$^{-1}$). Strong mass loss activity prior to explosion, such as those seen in SN~2009ip-like objects and SN~2021foa as precursor emission, are the likely origin of a complex, multiple-shell CSM close to the progenitor star.
format	Preprint
id	arxiv_https___arxiv_org_abs_2409_01359
institution	arXiv
publishDate	2024
record_format	arxiv
spellingShingle	SN 2021foa: The "Flip-Flop" Type IIn / Ibn supernova Farias, D. Gall, C. Narayan, G. Rest, S. Villar, V. A. Angus, C. R. Auchettl, K. Davis, K. W. Foley, R. Gagliano, A. Hjorth, J. Izzo, L. Kilpatrick, C. D. Perkins, H . M. L. Ramirez-Ruiz, E. Ransome, C. L. Sarangi, A. Yarza, R. Coulter, D. A. Jones, D. O. Khetan, N. Rest, A. Siebert, M. R. Swift, J. J. Taggart, K. Tinyanont, S. Wrubel, P. de Boer, T. J. L. Clever, K. E. Dhara, A. Gao, H. Lin, C. -C. High Energy Astrophysical Phenomena We present a comprehensive analysis of the photometric and spectroscopic evolution of SN~2021foa, unique among the class of transitional supernovae for repeatedly changing its spectroscopic appearance from hydrogen-to-helium-to-hydrogen-dominated (IIn-to-Ibn-to-IIn) within 50 days past peak brightness. The spectra exhibit multiple narrow ($\approx$ 300--600~km~s$^{-1}$) absorption lines of hydrogen, helium, calcium and iron together with broad helium emission lines with a full-width-at-half-maximum (FWHM) of $\sim 6000$~km~s$^{-1}$. For a steady, wind-mass loss regime, light curve modeling results in an ejecta mass of $\sim 8$ M$_{\odot}$ and CSM mass below 1 M$_{\odot}$, and an ejecta velocity consistent with the FWHM of the broad helium lines. We obtain a mass-loss rate of $\approx 2$ M$_{\odot} {\rm yr}^{-1}$. This mass-loss rate is three orders of magnitude larger than derived for normal Type II SNe. We estimate that the bulk of the CSM of SN~2021foa must have been expelled within half a year, about 15 years ago. Our analysis suggests that SN~2021foa had a helium rich ejecta which swept up a dense shell of hydrogen rich CSM shortly after explosion. At about 60 days past peak brightness, the photosphere recedes through the dense ejecta-CSM region, occulting much of the red-shifted emission of the hydrogen and helium lines, which results in observed blue-shift ($\sim -3000$~km~s$^{-1}$). Strong mass loss activity prior to explosion, such as those seen in SN~2009ip-like objects and SN~2021foa as precursor emission, are the likely origin of a complex, multiple-shell CSM close to the progenitor star.
title	SN 2021foa: The "Flip-Flop" Type IIn / Ibn supernova
topic	High Energy Astrophysical Phenomena
url	https://arxiv.org/abs/2409.01359