A JWST Medium Resolution MIRI Spectrum and Models of the Type Ia supernova 2021aefx at +415 d

• DOI: 10.48550/arxiv.2404.17043
• Publication Date: 2024-04-25
• Authors: C. Ashall; P. Hoêflich; E. Baron; M. Shahbandeh; J. M. DerKacy; K. Medler; B. J. Shappee; M. A. Tucker; E. Fereidouni; T. Mera; Jennifer E. Andrews; D. Baade; K. Azalee Bostroem; P. J. Brown; C. R. Burns; A. Burrow; Aleksandar Cikota; Thomas de Jaeger; A. Do; Yize Dong; I. Dominguez; Ori D. Fox; L. Galbany; E. Y. Hsiao; K. Krisciunas; B. Khaghani; S. Kumar; Jing Lü; J. R. Maund; P. A. Mazzali; N. Morrell; F. Patat; C. Pfeffer; M. M. Phillips; J. H. K. Schmidt; S. Stangl; C. P. Stevens; M. Stritzinger; N. B. Suntzeff; C. M. Telesco; Lifan Wang; Yi Yang
• Keywords: Type Ia supernovae; High Energy Astrophysical Phenomena (astro-ph.HE); FOS: Physical sciences; Astrophysics; 01 natural sciences; 520; QB460-466; Supernovae; Astrophysics - Solar and Stellar Astrophysics; http://astrothesaurus.org/uat/1728; 0103 physical sciences; [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]; Astrophysics - High Energy Astrophysical Phenomena; Solar and Stellar Astrophysics (astro-ph.SR); http://astrothesaurus.org/uat/1668

We present a JWST MIRI/MRS spectrum (5-27 $\mathrm{\mu}$m) of the Type Ia supernova (SN Ia), SN 2021aefx at $+415$ days past $B$-band maximum. The spectrum, which was obtained during iron-dominated nebular phase, has been analyzed in combination with previous observations 2021aefx, to provide first time series analysis an Ia. find temporal evolution [Co III] 11.888 $\mathrm{\mu}$m feature directly traces decay $^{56}$Co. spectra, line profiles, and their are off-center delayed-detonation models. Best fits were White Dwarf (WD) central densities $\rho_c=0.9-1.1\times 10^9$g cm$^{-3}$, WD mass M$_{\mathrm{WD}}$=1.33-1.35M$_\odot$, magnetic field $\approx10^6$G, deflagration-to-detonation transition $\approx$ 0.5 $M_\odot$ seen opposite sight observer. inner electron capture core is dominated by energy deposition from $\gamma$-rays whereas broader region positron deposition, placing +415 d transitional phase positron-dominated regime. formerly `flat-tilted' profile 9 now significant contribution [Ni IV], [Fe II], less [Ar III], alters shape as positrons excite mostly low-velocity Ar. Overall, strength stable Ni features transport rather than mass. Based on multi-dimensional models, our strongly supports single-spot, close-to-central ignition indication for pre-existing turbulent velocity field, excludes multiple-spot, ignition.