Ground-based and JWST Observations of SN 2022pul. II. Evidence from Nebular Spectroscopy for a Violent Merger in a Peculiar Type-Ia Supernova

Lindsey A. Kwok; Matthew R. Siebert; Joel Johansson; Saurabh W. Jha; Stephane Blondin; Luc Dessart; Ryan J. Foley; D. John Hillier; Conor Larison; Ruediger Pakmor; Tea Temim; Jennifer E. Andrews; Katie Auchettl; Carles Badenes; Barnabas Barna; K. Azalee Bostroem; Max J. Brenner Newman; Thomas G. Brink; Maria Jose Bustamante-Rosell; Yssavo Camacho-Neves; Alejandro Clocchiatti; David A. Coulter; Kyle W. Davis; Maxime Deckers; Georgios Dimitriadis; Yize Dong; Joseph Farah; Alexei V. Filippenko; Andreas Flors; Ori D. Fox; Peter Garnavich; Estefania Padilla Gonzalez; Or Graur; Franz-Josef Hambsch; Griffin Hosseinzadeh; D. Andrew Howell; John P. Hughes; Wolfgang E. Kerzendorf; Xavier K. Le Saux; Keiichi Maeda; Kate Maguire; Curtis McCully; Cassidy Mihalenko; Megan Newsome; John T. O'Brien; Jeniveve Pearson; Craig Pellegrino; Justin D. R. Pierel; Abigail Polin; Armin Rest; Cesar Rojas-Bravo; David J. Sand; Michaela Schwab; Melissa Shahbandeh; Manisha Shrestha; Nathan Smith; Louis-Gregory Strolger; Tamas Szalai; Kirsty Taggart; Giacomo Terreran; Jacco H. Terwel; Samaporn Tinyanont; Stefano Valenti; Jozsef Vinko; J. Craig Wheeler; Yi Yang; WeiKang Zheng; Chris Ashall; James M. DerKacy; Lluis Galbany; Peter Hoeflich; Thomas de Jaeger; Jing Lu; Justyn Maund; Kyle Medler; Nidia Morrell; Benjamin J. Shappee; Maximilian Stritzinger; Nicholas Suntzeff; Michael Tucker; Lifan Wang

doi:10.3847/1538-4357/ad2c0d

Ground-based and JWST Observations of SN 2022pul. II. Evidence from Nebular Spectroscopy for a Violent Merger in a Peculiar Type-Ia Supernova

Lindsey A. Kwok, Matthew R. Siebert, Joel Johansson, Saurabh W. Jha, Stephane Blondin, Luc Dessart, Ryan J. Foley, D. John Hillier, Conor Larison, Ruediger Pakmor, Tea Temim, Jennifer E. Andrews, Katie Auchettl, Carles Badenes, Barnabas Barna, K. Azalee Bostroem, Max J. Brenner Newman, Thomas G. Brink, Maria Jose Bustamante-Rosell, Yssavo Camacho-NevesAlejandro Clocchiatti, David A. Coulter, Kyle W. Davis, Maxime Deckers, Georgios Dimitriadis, Yize Dong, Joseph Farah, Alexei V. Filippenko, Andreas Flors, Ori D. Fox, Peter Garnavich, Estefania Padilla Gonzalez, Or Graur, Franz-Josef Hambsch, Griffin Hosseinzadeh, D. Andrew Howell, John P. Hughes, Wolfgang E. Kerzendorf, Xavier K. Le Saux, Keiichi Maeda, Kate Maguire, Curtis McCully, Cassidy Mihalenko, Megan Newsome, John T. O'Brien, Jeniveve Pearson, Craig Pellegrino, Justin D. R. Pierel, Abigail Polin, Armin Rest, Cesar Rojas-Bravo, David J. Sand, Michaela Schwab, Melissa Shahbandeh, Manisha Shrestha, Nathan Smith, Louis-Gregory Strolger, Tamas Szalai, Kirsty Taggart, Giacomo Terreran, Jacco H. Terwel, Samaporn Tinyanont, Stefano Valenti, Jozsef Vinko, J. Craig Wheeler, Yi Yang, WeiKang Zheng, Chris Ashall, James M. DerKacy, Lluis Galbany, Peter Hoeflich, Thomas de Jaeger, Jing Lu, Justyn Maund, Kyle Medler, Nidia Morrell, Benjamin J. Shappee, Maximilian Stritzinger, Nicholas Suntzeff, Michael Tucker, Lifan Wang

Institute of Cosmology & Gravitation

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Abstract

We present an analysis of ground-based and JWST observations of SN 2022pul, a peculiar "03fg-like" (or "super-Chandrasekhar") Type Ia supernova (SN Ia), in the nebular phase at 338 d post explosion. Our combined spectrum continuously covers 0.4-14 $\mu$m and includes the first mid-infrared spectrum of an 03fg-like SN Ia. Compared to normal SN Ia 2021aefx, SN 2022pul exhibits a lower mean ionization state, asymmetric emission-line profiles, stronger emission from the intermediate-mass elements (IMEs) argon and calcium, weaker emission from iron-group elements (IGEs), and the first unambiguous detection of neon in a SN Ia. Strong, broad, centrally peaked [Ne II] at 12.81 $\mu$m was previously predicted as a hallmark of "violent merger'' SN Ia models, where dynamical interaction between two sub-$M_{\text{Ch}}$ white dwarfs (WDs) causes disruption of the lower mass WD and detonation of the other. The violent merger scenario was already a leading hypothesis for 03fg-like SNe Ia; in SN 2022pul it can explain the large-scale ejecta asymmetries seen between the IMEs and IGEs and the central location of narrow oxygen and broad neon. We modify extant models to add clumping of the central ejecta to better reproduce the optical iron emission, and add mass in the innermost region ($< 2000$ km s$^{-1}$) to account for the observed narrow [O I] $\lambda\lambda6300$, 6364 emission. A violent WD-WD merger explains many of the observations of SN 2022pul, and our results favor this model interpretation for the subclass of 03fg-like SN Ia.

Original language	English
Article number	135
Number of pages	18
Journal	The Astrophysical Journal
Volume	966
Issue number	1
DOIs	https://doi.org/10.3847/1538-4357/ad2c0d
Publication status	Published - 1 May 2024

Keywords

astro-ph.HE
astro-ph.SR

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10.3847/1538-4357/ad2c0d

Ground-based and JWST Observations of SN 2022pulFinal published version, 2.67 MBLicence: CC BY

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Kwok, L. A., Siebert, M. R., Johansson, J., Jha, S. W., Blondin, S., Dessart, L., Foley, R. J., Hillier, D. J., Larison, C., Pakmor, R., Temim, T., Andrews, J. E., Auchettl, K., Badenes, C., Barna, B., Bostroem, K. A., Newman, M. J. B., Brink, T. G., Bustamante-Rosell, M. J., ... Wang, L. (2024). Ground-based and JWST Observations of SN 2022pul. II. Evidence from Nebular Spectroscopy for a Violent Merger in a Peculiar Type-Ia Supernova. The Astrophysical Journal, 966(1), Article 135. https://doi.org/10.3847/1538-4357/ad2c0d

@article{f929fc003b884503bf947366a2297298,

title = "Ground-based and JWST Observations of SN 2022pul. II. Evidence from Nebular Spectroscopy for a Violent Merger in a Peculiar Type-Ia Supernova",

abstract = " We present an analysis of ground-based and JWST observations of SN 2022pul, a peculiar {"}03fg-like{"} (or {"}super-Chandrasekhar{"}) Type Ia supernova (SN Ia), in the nebular phase at 338 d post explosion. Our combined spectrum continuously covers 0.4-14 $\mu$m and includes the first mid-infrared spectrum of an 03fg-like SN Ia. Compared to normal SN Ia 2021aefx, SN 2022pul exhibits a lower mean ionization state, asymmetric emission-line profiles, stronger emission from the intermediate-mass elements (IMEs) argon and calcium, weaker emission from iron-group elements (IGEs), and the first unambiguous detection of neon in a SN Ia. Strong, broad, centrally peaked [Ne II] at 12.81 $\mu$m was previously predicted as a hallmark of {"}violent merger'' SN Ia models, where dynamical interaction between two sub-$M_{\text{Ch}}$ white dwarfs (WDs) causes disruption of the lower mass WD and detonation of the other. The violent merger scenario was already a leading hypothesis for 03fg-like SNe Ia; in SN 2022pul it can explain the large-scale ejecta asymmetries seen between the IMEs and IGEs and the central location of narrow oxygen and broad neon. We modify extant models to add clumping of the central ejecta to better reproduce the optical iron emission, and add mass in the innermost region ($< 2000$ km s$^{-1}$) to account for the observed narrow [O I] $\lambda\lambda6300$, 6364 emission. A violent WD-WD merger explains many of the observations of SN 2022pul, and our results favor this model interpretation for the subclass of 03fg-like SN Ia. ",

keywords = "astro-ph.HE, astro-ph.SR",

author = "Kwok, {Lindsey A.} and Siebert, {Matthew R.} and Joel Johansson and Jha, {Saurabh W.} and Stephane Blondin and Luc Dessart and Foley, {Ryan J.} and Hillier, {D. John} and Conor Larison and Ruediger Pakmor and Tea Temim and Andrews, {Jennifer E.} and Katie Auchettl and Carles Badenes and Barnabas Barna and Bostroem, {K. Azalee} and Newman, {Max J. Brenner} and Brink, {Thomas G.} and Bustamante-Rosell, {Maria Jose} and Yssavo Camacho-Neves and Alejandro Clocchiatti and Coulter, {David A.} and Davis, {Kyle W.} and Maxime Deckers and Georgios Dimitriadis and Yize Dong and Joseph Farah and Filippenko, {Alexei V.} and Andreas Flors and Fox, {Ori D.} and Peter Garnavich and Gonzalez, {Estefania Padilla} and Or Graur and Franz-Josef Hambsch and Griffin Hosseinzadeh and Howell, {D. Andrew} and Hughes, {John P.} and Kerzendorf, {Wolfgang E.} and Saux, {Xavier K. Le} and Keiichi Maeda and Kate Maguire and Curtis McCully and Cassidy Mihalenko and Megan Newsome and O'Brien, {John T.} and Jeniveve Pearson and Craig Pellegrino and Pierel, {Justin D. R.} and Abigail Polin and Armin Rest and Cesar Rojas-Bravo and Sand, {David J.} and Michaela Schwab and Melissa Shahbandeh and Manisha Shrestha and Nathan Smith and Louis-Gregory Strolger and Tamas Szalai and Kirsty Taggart and Giacomo Terreran and Terwel, {Jacco H.} and Samaporn Tinyanont and Stefano Valenti and Jozsef Vinko and Wheeler, {J. Craig} and Yi Yang and WeiKang Zheng and Chris Ashall and DerKacy, {James M.} and Lluis Galbany and Peter Hoeflich and Jaeger, {Thomas de} and Jing Lu and Justyn Maund and Kyle Medler and Nidia Morrell and Shappee, {Benjamin J.} and Maximilian Stritzinger and Nicholas Suntzeff and Michael Tucker and Lifan Wang",

note = "20 pages, 10 figures, submitted to ApJ",

year = "2024",

month = may,

day = "1",

doi = "10.3847/1538-4357/ad2c0d",

language = "English",

volume = "966",

journal = "The Astrophysical Journal",

issn = "0004-637X",

publisher = "IOP Publishing",

number = "1",

}

Kwok, LA, Siebert, MR, Johansson, J, Jha, SW, Blondin, S, Dessart, L, Foley, RJ, Hillier, DJ, Larison, C, Pakmor, R, Temim, T, Andrews, JE, Auchettl, K, Badenes, C, Barna, B, Bostroem, KA, Newman, MJB, Brink, TG, Bustamante-Rosell, MJ, Camacho-Neves, Y, Clocchiatti, A, Coulter, DA, Davis, KW, Deckers, M, Dimitriadis, G, Dong, Y, Farah, J, Filippenko, AV, Flors, A, Fox, OD, Garnavich, P, Gonzalez, EP, Graur, O, Hambsch, F-J, Hosseinzadeh, G, Howell, DA, Hughes, JP, Kerzendorf, WE, Saux, XKL, Maeda, K, Maguire, K, McCully, C, Mihalenko, C, Newsome, M, O'Brien, JT, Pearson, J, Pellegrino, C, Pierel, JDR, Polin, A, Rest, A, Rojas-Bravo, C, Sand, DJ, Schwab, M, Shahbandeh, M, Shrestha, M, Smith, N, Strolger, L-G, Szalai, T, Taggart, K, Terreran, G, Terwel, JH, Tinyanont, S, Valenti, S, Vinko, J, Wheeler, JC, Yang, Y, Zheng, W, Ashall, C, DerKacy, JM, Galbany, L, Hoeflich, P, Jaeger, TD, Lu, J, Maund, J, Medler, K, Morrell, N, Shappee, BJ, Stritzinger, M, Suntzeff, N, Tucker, M & Wang, L 2024, 'Ground-based and JWST Observations of SN 2022pul. II. Evidence from Nebular Spectroscopy for a Violent Merger in a Peculiar Type-Ia Supernova', The Astrophysical Journal, vol. 966, no. 1, 135. https://doi.org/10.3847/1538-4357/ad2c0d

TY - JOUR

T1 - Ground-based and JWST Observations of SN 2022pul. II. Evidence from Nebular Spectroscopy for a Violent Merger in a Peculiar Type-Ia Supernova

AU - Kwok, Lindsey A.

AU - Siebert, Matthew R.

AU - Johansson, Joel

AU - Jha, Saurabh W.

AU - Blondin, Stephane

AU - Dessart, Luc

AU - Foley, Ryan J.

AU - Hillier, D. John

AU - Larison, Conor

AU - Pakmor, Ruediger

AU - Temim, Tea

AU - Andrews, Jennifer E.

AU - Auchettl, Katie

AU - Badenes, Carles

AU - Barna, Barnabas

AU - Bostroem, K. Azalee

AU - Newman, Max J. Brenner

AU - Brink, Thomas G.

AU - Bustamante-Rosell, Maria Jose

AU - Camacho-Neves, Yssavo

AU - Clocchiatti, Alejandro

AU - Coulter, David A.

AU - Davis, Kyle W.

AU - Deckers, Maxime

AU - Dimitriadis, Georgios

AU - Dong, Yize

AU - Farah, Joseph

AU - Filippenko, Alexei V.

AU - Flors, Andreas

AU - Fox, Ori D.

AU - Garnavich, Peter

AU - Gonzalez, Estefania Padilla

AU - Graur, Or

AU - Hambsch, Franz-Josef

AU - Hosseinzadeh, Griffin

AU - Howell, D. Andrew

AU - Hughes, John P.

AU - Kerzendorf, Wolfgang E.

AU - Saux, Xavier K. Le

AU - Maeda, Keiichi

AU - Maguire, Kate

AU - McCully, Curtis

AU - Mihalenko, Cassidy

AU - Newsome, Megan

AU - O'Brien, John T.

AU - Pearson, Jeniveve

AU - Pellegrino, Craig

AU - Pierel, Justin D. R.

AU - Polin, Abigail

AU - Rest, Armin

AU - Rojas-Bravo, Cesar

AU - Sand, David J.

AU - Schwab, Michaela

AU - Shahbandeh, Melissa

AU - Shrestha, Manisha

AU - Smith, Nathan

AU - Strolger, Louis-Gregory

AU - Szalai, Tamas

AU - Taggart, Kirsty

AU - Terreran, Giacomo

AU - Terwel, Jacco H.

AU - Tinyanont, Samaporn

AU - Valenti, Stefano

AU - Vinko, Jozsef

AU - Wheeler, J. Craig

AU - Yang, Yi

AU - Zheng, WeiKang

AU - Ashall, Chris

AU - DerKacy, James M.

AU - Galbany, Lluis

AU - Hoeflich, Peter

AU - Jaeger, Thomas de

AU - Lu, Jing

AU - Maund, Justyn

AU - Medler, Kyle

AU - Morrell, Nidia

AU - Shappee, Benjamin J.

AU - Stritzinger, Maximilian

AU - Suntzeff, Nicholas

AU - Tucker, Michael

AU - Wang, Lifan

N1 - 20 pages, 10 figures, submitted to ApJ

PY - 2024/5/1

Y1 - 2024/5/1

N2 - We present an analysis of ground-based and JWST observations of SN 2022pul, a peculiar "03fg-like" (or "super-Chandrasekhar") Type Ia supernova (SN Ia), in the nebular phase at 338 d post explosion. Our combined spectrum continuously covers 0.4-14 $\mu$m and includes the first mid-infrared spectrum of an 03fg-like SN Ia. Compared to normal SN Ia 2021aefx, SN 2022pul exhibits a lower mean ionization state, asymmetric emission-line profiles, stronger emission from the intermediate-mass elements (IMEs) argon and calcium, weaker emission from iron-group elements (IGEs), and the first unambiguous detection of neon in a SN Ia. Strong, broad, centrally peaked [Ne II] at 12.81 $\mu$m was previously predicted as a hallmark of "violent merger'' SN Ia models, where dynamical interaction between two sub-$M_{\text{Ch}}$ white dwarfs (WDs) causes disruption of the lower mass WD and detonation of the other. The violent merger scenario was already a leading hypothesis for 03fg-like SNe Ia; in SN 2022pul it can explain the large-scale ejecta asymmetries seen between the IMEs and IGEs and the central location of narrow oxygen and broad neon. We modify extant models to add clumping of the central ejecta to better reproduce the optical iron emission, and add mass in the innermost region ($< 2000$ km s$^{-1}$) to account for the observed narrow [O I] $\lambda\lambda6300$, 6364 emission. A violent WD-WD merger explains many of the observations of SN 2022pul, and our results favor this model interpretation for the subclass of 03fg-like SN Ia.

AB - We present an analysis of ground-based and JWST observations of SN 2022pul, a peculiar "03fg-like" (or "super-Chandrasekhar") Type Ia supernova (SN Ia), in the nebular phase at 338 d post explosion. Our combined spectrum continuously covers 0.4-14 $\mu$m and includes the first mid-infrared spectrum of an 03fg-like SN Ia. Compared to normal SN Ia 2021aefx, SN 2022pul exhibits a lower mean ionization state, asymmetric emission-line profiles, stronger emission from the intermediate-mass elements (IMEs) argon and calcium, weaker emission from iron-group elements (IGEs), and the first unambiguous detection of neon in a SN Ia. Strong, broad, centrally peaked [Ne II] at 12.81 $\mu$m was previously predicted as a hallmark of "violent merger'' SN Ia models, where dynamical interaction between two sub-$M_{\text{Ch}}$ white dwarfs (WDs) causes disruption of the lower mass WD and detonation of the other. The violent merger scenario was already a leading hypothesis for 03fg-like SNe Ia; in SN 2022pul it can explain the large-scale ejecta asymmetries seen between the IMEs and IGEs and the central location of narrow oxygen and broad neon. We modify extant models to add clumping of the central ejecta to better reproduce the optical iron emission, and add mass in the innermost region ($< 2000$ km s$^{-1}$) to account for the observed narrow [O I] $\lambda\lambda6300$, 6364 emission. A violent WD-WD merger explains many of the observations of SN 2022pul, and our results favor this model interpretation for the subclass of 03fg-like SN Ia.

KW - astro-ph.HE

KW - astro-ph.SR

U2 - 10.3847/1538-4357/ad2c0d

DO - 10.3847/1538-4357/ad2c0d

M3 - Article

SN - 0004-637X

VL - 966

JO - The Astrophysical Journal

JF - The Astrophysical Journal

IS - 1

M1 - 135

ER -

Ground-based and JWST Observations of SN 2022pul. II. Evidence from Nebular Spectroscopy for a Violent Merger in a Peculiar Type-Ia Supernova

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