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JWST Low-resolution MIRI Spectral Observations of SN 2021aefx: High-density Burning in a Type Ia Supernova

DerKacy, JM, Ashall, C, Hoeflich, P, Baron, E, Shappee, BJ, Baade, D, Andrews, J, Bostroem, KA, Brown, PJ, Burns, CR, Burrow, A, Cikota, A, de Jaeger, T, Do, A, Dong, Y, Dominguez, I, Galbany, L, Hsiao, EY, Karamehmetoglu, E, Krisciunas, K , Kumar, S, Lu, J, Evans, TBM, Maund, JR, Mazzali, P, Medler, K, Morrell, N, Patat, F, Phillips, MM, Shahbandeh, M, Stangl, S, Stevens, CP, Stritzinger, MD, Suntzeff, NB, Telesco, CM, Tucker, MA, Valenti, S, Wang, L, Yang, Y, Jha, SW and Kwok, LA (2023) JWST Low-resolution MIRI Spectral Observations of SN 2021aefx: High-density Burning in a Type Ia Supernova. Astrophysical Journal Letters, 945 (1). ISSN 2041-8205

JWST Low-resolution MIRI Spectral Observations of SN 2021aefx High-density Burning in a Type 1a Supernova.pdf - Published Version
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Open Access URL: https://doi.org/10.3847/2041-8213/acb8a8 (Published version)


We present a JWST/MIRI low-resolution mid-infrared (MIR) spectroscopic observation of the normal Type Ia supernova (SN Ia) SN 2021aefx at +323 days past rest-frame B-band maximum light. The spectrum ranges from 4 to 14 μm and shows many unique qualities, including a flat-topped [Ar iii] 8.991 μm profile, a strongly tilted [Co iii] 11.888 μm feature, and multiple stable Ni lines. These features provide critical information about the physics of the explosion. The observations are compared to synthetic spectra from detailed non-local thermodynamic equilibrium multidimensional models. The results of the best-fitting model are used to identify the components of the spectral blends and provide a quantitative comparison to the explosion physics. Emission line profiles and the presence of electron capture elements are used to constrain the mass of the exploding white dwarf (WD) and the chemical asymmetries in the ejecta. We show that the observations of SN 2021aefx are consistent with an off-center delayed detonation explosion of a near-Chandrasekhar mass (M Ch) WD at a viewing angle of −30° relative to the point of the deflagration to detonation transition. From the strengths of the stable Ni lines, we determine that there is little to no mixing in the central regions of the ejecta. Based on both the presence of stable Ni and the Ar velocity distributions, we obtain a strict lower limit of 1.2 M ⊙ for the initial WD, implying that most sub-M Ch explosions models are not viable models for SN 2021aefx. The analysis here shows the crucial importance of MIR spectra in distinguishing between explosion scenarios for SNe Ia.

Item Type: Article
Uncontrolled Keywords: 0201 Astronomical and Space Sciences; Astronomy & Astrophysics
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: American Astronomical Society
SWORD Depositor: A Symplectic
Date Deposited: 22 Mar 2023 12:51
Last Modified: 22 Mar 2023 13:00
DOI or ID number: 10.3847/2041-8213/acb8a8
URI: https://researchonline.ljmu.ac.uk/id/eprint/19151
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