DerKacy, JM, Ashall, C, Hoeflich, P, Baron, E, Shahbandeh, M, Shappee, BJ, Andrews, J, Baade, D, Balangan, EF, Bostroem, KA, Brown, PJ, Burns, CR, Burrow, A, Cikota, A, De Jaeger, T, Do, A, Dong, Y, Dominguez, I, Fox, O, Galbany, L et al, Hoang, ET, Hsiao, EY, Janzen, D, Jencson, JE, Krisciunas, K, Kumar, S, Lu, J, Lundquist, M, Mera Evans, TB, Maund, JR, Mazzali, P, Medler, K, Meza Retamal, NE, Morrell, N, Patat, F, Pearson, J, Phillips, MM, Shrestha, M, Stangl, S, Stevens, CP, Stritzinger, MD, Suntzeff, NB, Telesco, CM, Tucker, MA, Valenti, S, Wang, L and Yang, Y (2024) JWST MIRI /Medium Resolution Spectrograph (MRS) Observations and Spectral Models of the Underluminous Type Ia Supernova 2022xkq. Astrophysical Journal, 961 (2). ISSN 0004-637X

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Abstract

We present a JWST mid-infrared spectrum of the under-luminous Type Ia Supernova (SN Ia) 2022xkq, obtained with the medium-resolution spectrometer on the Mid-Infrared Instrument (MIRI) ~ 130 days post-explosion. We identify the first MIR lines beyond 14 um in SN Ia observations. We find features unique to under luminous SNe Ia, including: isolated emission of stable Ni, strong blends of [Ti II], and large ratios of singly ionized to doubly ionized species in both [Ar] and [Co]. Comparisons to normal-luminosity SNe Ia spectra at similar phases show a tentative trend between the width of the [Co III] 11.888 um feature and the SN light curve shape. Using non-LTE-multi-dimensional radiation hydro simulations and the observed electron capture elements we constrain the mass of the exploding white dwarf. The best-fitting model shows that SN 2022xkq is consistent with an off-center delayed-detonation explosion of a near-Chandrasekhar mass WD (Mej ≈ 1.37 M⊙) of high-central density (ρc≥2.0×109 g cm−3) seen equator on, which produced M(56Ni) =0.324 M⊙ and M(58Ni) ≥0.06 M⊙. The observed line widths are consistent with the overall abundance distribution; and the narrow stable Ni lines indicate little to no mixing in the central regions, favoring central ignition of sub-sonic carbon burning followed by an off-center DDT beginning at a single point. Additional observations may further constrain the physics revealing the presence of additional species including Cr and Mn. Our work demonstrates the power of using the full coverage of MIRI in combination with detailed modeling to elucidate the physics of SNe Ia at a level not previously possible.

Item Type:	Article
Uncontrolled Keywords:	astro-ph.HE; astro-ph.HE; astro-ph.SR
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	American Astronomical Society; IOP Publishing
Related URLs:	http://arxiv.org/abs/2310.09153v2
SWORD Depositor:	A Symplectic
Date Deposited:	08 Feb 2024 09:40
Last Modified:	08 Feb 2024 09:45
DOI or ID number:	10.3847/1538-4357/ad0b7b
URI:	https://researchonline.ljmu.ac.uk/id/eprint/22535

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