A JWST Near- and Mid-infrared Nebular Spectrum of the Type Ia Supernova 2021aefx

0571135 - ASÚ 2024 RIV US eng J - Journal Article
Kwok, L. A. - Jha, S. W. - Temim, T. - Barna, Barnabas … Total 58 authors
A JWST Near- and Mid-infrared Nebular Spectrum of the Type Ia Supernova 2021aefx.
Astrophysical Journal Letters. Roč. 944, č. 1 (2023), č. článku L3. ISSN 2041-8205. E-ISSN 2041-8213
Institutional support: RVO:67985815
Keywords : supernovae * type Ia supernovae * white dwarf stars
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 7.9, year: 2022
Method of publishing: Open access

We present JWST near-infrared (NIR) and mid-infrared (MIR) spectroscopic observations of the nearby normal Type Ia supernova (SN) SN 2021aefx in the nebular phase at +255 days past maximum light. Our Near Infrared Spectrograph (NIRSpec) and Mid Infrared Instrument observations, combined with ground-based optical data from the South African Large Telescope, constitute the first complete optical+NIR+MIR nebular SN Ia spectrum covering 0.3-14 mu m. This spectrum unveils the previously unobserved 2.5-5 mu m region, revealing strong nebular iron and stable nickel emission, indicative of high-density burning that can constrain the progenitor mass. The data show a significant improvement in sensitivity and resolution compared to previous Spitzer MIR data. We identify numerous NIR and MIR nebular emission lines from iron-group elements as well as lines from the intermediate-mass element argon. The argon lines extend to higher velocities than the iron-group elements, suggesting stratified ejecta that are a hallmark of delayed-detonation or double-detonation SN Ia models. We present fits to simple geometric line profiles to features beyond 1.2 mu m and find that most lines are consistent with Gaussian or spherical emission distributions, while the [Ar iii] 8.99 mu m line has a distinctively flat-topped profile indicating a thick spherical shell of emission. Using our line profile fits, we investigate the emissivity structure of SN 2021aefx and measure kinematic properties. Continued observations of SN 2021aefx and other SNe Ia with JWST will be transformative to the study of SN Ia composition, ionization structure, density, and temperature, and will provide important constraints on SN Ia progenitor and explosion models.
Permanent Link: https://hdl.handle.net/11104/0342427