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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2510.09760 |
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| _version_ | 1866914091967184896 |
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| author | Kwok, Lindsey A. Liu, Chang Jha, Saurabh W. Blondin, Stéphane Larison, Conor Miller, Adam A. Dai, Mi Foley, Ryan J. Filippenko, Alexei V. Andrews, Jennifer E. Andrews, Moira Auchettl, Katie Badenes, Carles Brink, Thomas G. Davis, Kyle W. Flörs, Andreas Galbany, Lluís Graur, Or Howell, D. Andrew Kumar, Sahana Könyves-Tóth, Réka LeBaron, Natalie Macrie, Colin W. Maeda, Keiichi Maguire, Kate McCully, Curtis Meza-Retamal, Nicolas E. Gonzalez, Estefania Padilla Pakmor, Rüdiger Pearson, Jeniveve Piro, Anthony L. Polin, Abigail Rehemtulla, Nabeel Rojas-Bravo, César Sand, David J. Sangkachan, Chita Schwab, Michaela Sears, Huei Singh, Mridweeka Subrayan, Bhagya M. Taggart, Kirsty Temim, Tea Terwel, Jacco H. Tinyanont, Samaporn Vinkó, József Wang, Xiaofeng Wheeler, J. Craig Yang, Yi Zheng, WeiKang |
| author_facet | Kwok, Lindsey A. Liu, Chang Jha, Saurabh W. Blondin, Stéphane Larison, Conor Miller, Adam A. Dai, Mi Foley, Ryan J. Filippenko, Alexei V. Andrews, Jennifer E. Andrews, Moira Auchettl, Katie Badenes, Carles Brink, Thomas G. Davis, Kyle W. Flörs, Andreas Galbany, Lluís Graur, Or Howell, D. Andrew Kumar, Sahana Könyves-Tóth, Réka LeBaron, Natalie Macrie, Colin W. Maeda, Keiichi Maguire, Kate McCully, Curtis Meza-Retamal, Nicolas E. Gonzalez, Estefania Padilla Pakmor, Rüdiger Pearson, Jeniveve Piro, Anthony L. Polin, Abigail Rehemtulla, Nabeel Rojas-Bravo, César Sand, David J. Sangkachan, Chita Schwab, Michaela Sears, Huei Singh, Mridweeka Subrayan, Bhagya M. Taggart, Kirsty Temim, Tea Terwel, Jacco H. Tinyanont, Samaporn Vinkó, József Wang, Xiaofeng Wheeler, J. Craig Yang, Yi Zheng, WeiKang |
| contents | We present optical + near-infrared (NIR) + mid-infrared (MIR) observations of the normal Type Ia supernovae (SN Ia) 2022aaiq and 2024gy in the nebular phase, continuously spanning 0.35-28 microns. Medium-resolution JWST spectroscopy reveals novel narrow ($v_{\mathrm{FWHM}}<1500$ km s$^{-1}$) [Ni II] 1.94 and 6.64 micron cores in both events. The MIR [Ni II] 6.64 micron line exhibits a distinct narrow core atop a broader base, indicating a central enhancement of stable Ni. This structure points to high central densities consistent with a near-Chandrasekhar-mass ($M_{Ch}$) progenitor or a high-metallicity sub-$M_{Ch}$ progenitor. From detailed line-profile inversions of SN 2024gy, we derive emissivity profiles for stable iron-group elements (IGEs), radioactive material, and intermediate-mass elements (IMEs), revealing spatially distinct ejecta zones. The [Ni III] 7.35 micron line shows a shallow-to-steep slope transition -- a "broken-slope" morphology -- that matches predictions for delayed detonation explosions with separated deflagration and detonation ashes. We also reanalyze and compare to archival JWST spectra of SN 2021aefx and the subluminous SN 2022xkq. We estimate a stable $^{58}$Ni mass of $\sim0.1$ M$_\odot$ for SN 2024gy, consistent with delayed detonation models, and $\sim0.01$ M$_\odot$ for SN 2022xkq, favoring sub-$M_{Ch}$ scenarios. These results demonstrate that resolved line profiles, now accessible with JWST, provide powerful diagnostics of explosion geometry, central density, and progenitor mass in SN Ia. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_09760 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | JWST Spectroscopy of SN Ia 2022aaiq and 2024gy: Evidence for Enhanced Central Stable Ni Abundance and a Deflagration-to-Detonation Transition Kwok, Lindsey A. Liu, Chang Jha, Saurabh W. Blondin, Stéphane Larison, Conor Miller, Adam A. Dai, Mi Foley, Ryan J. Filippenko, Alexei V. Andrews, Jennifer E. Andrews, Moira Auchettl, Katie Badenes, Carles Brink, Thomas G. Davis, Kyle W. Flörs, Andreas Galbany, Lluís Graur, Or Howell, D. Andrew Kumar, Sahana Könyves-Tóth, Réka LeBaron, Natalie Macrie, Colin W. Maeda, Keiichi Maguire, Kate McCully, Curtis Meza-Retamal, Nicolas E. Gonzalez, Estefania Padilla Pakmor, Rüdiger Pearson, Jeniveve Piro, Anthony L. Polin, Abigail Rehemtulla, Nabeel Rojas-Bravo, César Sand, David J. Sangkachan, Chita Schwab, Michaela Sears, Huei Singh, Mridweeka Subrayan, Bhagya M. Taggart, Kirsty Temim, Tea Terwel, Jacco H. Tinyanont, Samaporn Vinkó, József Wang, Xiaofeng Wheeler, J. Craig Yang, Yi Zheng, WeiKang High Energy Astrophysical Phenomena We present optical + near-infrared (NIR) + mid-infrared (MIR) observations of the normal Type Ia supernovae (SN Ia) 2022aaiq and 2024gy in the nebular phase, continuously spanning 0.35-28 microns. Medium-resolution JWST spectroscopy reveals novel narrow ($v_{\mathrm{FWHM}}<1500$ km s$^{-1}$) [Ni II] 1.94 and 6.64 micron cores in both events. The MIR [Ni II] 6.64 micron line exhibits a distinct narrow core atop a broader base, indicating a central enhancement of stable Ni. This structure points to high central densities consistent with a near-Chandrasekhar-mass ($M_{Ch}$) progenitor or a high-metallicity sub-$M_{Ch}$ progenitor. From detailed line-profile inversions of SN 2024gy, we derive emissivity profiles for stable iron-group elements (IGEs), radioactive material, and intermediate-mass elements (IMEs), revealing spatially distinct ejecta zones. The [Ni III] 7.35 micron line shows a shallow-to-steep slope transition -- a "broken-slope" morphology -- that matches predictions for delayed detonation explosions with separated deflagration and detonation ashes. We also reanalyze and compare to archival JWST spectra of SN 2021aefx and the subluminous SN 2022xkq. We estimate a stable $^{58}$Ni mass of $\sim0.1$ M$_\odot$ for SN 2024gy, consistent with delayed detonation models, and $\sim0.01$ M$_\odot$ for SN 2022xkq, favoring sub-$M_{Ch}$ scenarios. These results demonstrate that resolved line profiles, now accessible with JWST, provide powerful diagnostics of explosion geometry, central density, and progenitor mass in SN Ia. |
| title | JWST Spectroscopy of SN Ia 2022aaiq and 2024gy: Evidence for Enhanced Central Stable Ni Abundance and a Deflagration-to-Detonation Transition |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2510.09760 |