Nebular spectra from Type Ia supernova explosion models compared to JWST observations of SN 2021aefx

Abstract

Recent JWST observations of the Type Ia supernova (SN Ia) 2021aefx in the nebular phase have paved the way for late-time studies covering the full optical to mid-infrared (MIR) wavelength range, and with it the hope to better constrain SN Ia explosion mechanisms. We investigate whether public SN Ia models covering a broad range of progenitor scenarios and explosion mechanisms can reproduce the full optical-MIR spectrum of SN 2021aefx at $\sim$270 days post explosion. We performed 1D steady-state non-LTE simulations with the radiative-transfer code CMFGEN, and compared the predicted spectra to SN 2021aefx. The models can explain the main features of SN 2021aefx over the full wavelength range. However, no single model, or mechanism, emerges as a preferred match. We discuss possible causes for the mismatch of the models, including ejecta asymmetries and ionisation effects. Our new calculations of the collisional strengths for Ni III have a major impact on the two prominent lines at 7.35 and 11.00 $\mu$m, and highlight the need for more accurate collisional data for forbidden transitions. Using updated atomic data, we identify a strong feature due to [Ca IV] 3.21 $\mu$m, attributed to [Ni I] in previous studies. We also provide a tentative identification of a forbidden line due to [Ne II] 12.81 $\mu$m, whose peaked profile indicates the presence of neon all the way to the innermost region of the ejecta, as predicted for instance in violent merger models. Contrary to previous claims, we show that the [Ar III] 8.99 $\mu$m line can be broader in sub-$M_{\mathrm{Ch}}$ models compared to near-$M_{\mathrm{Ch}}$ models. Our models suggest that key physical ingredients are missing from either the explosion models, or the radiative-transfer post-processing, or both. Nonetheless, they also show the potential of the near- and MIR to uncover new spectroscopic diagnostics of SN Ia explosion mechanisms.

arXiv commentAccepted for publication in A&A. Revised version includes new figures, tables, and appendices. The input models and synthetic spectra are available at https://zenodo.org/record/8290155 . The complete collisional data for Ni III are available at the CDS at https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/678/A170

References in corpus (52)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• Observational clues to the progenitors of Type-Ia supernovae
• Three-dimensional delayed-detonation models with nucleosynthesis for Type Ia supernovae
• Explosion Models for Type Ia Supernovae: A Comparison with Observed Light Curves, distances, H_o and q_o
• Normal Type Ia supernovae from violent mergers of white dwarf binaries
• Sub-luminous type Ia supernovae from the mergers of equal-mass white dwarfs with M~0.9 M_sun
• Type Ia Supernovae: Influence of the Initial Composition on the Nucleosynthesis, Light Curves, Spectra and Consequences for the Determination of Omega_M & Lambda
• Three-dimensional pure deflagration models with nucleosynthesis and synthetic observables for Type Ia supernovae
• Three-Dimensional Delayed-Detonation Model of Type Ia Supernova
• Sub-Chandrasekhar-mass white dwarf detonations revisited
• The progenitor mass of the Type IIP supernova SN 2004et from late-time spectral modeling
• Time Dependent Radiative Transfer Calculations for Supernovae
• On Type Ia Supernovae From The Collisions of Two White Dwarfs
• Precision Measurement of the Lifetime of the 3d D_{5/2} state in 40Ca+
• Signatures of Delayed Detonation, Asymmetry, and Electron Capture in the Mid-Infrared Spectra of Supernovae 2003hv and 2005df
• Evidence for sub-Chandrasekhar-mass progenitors of Type Ia supernovae at the faint end of the width-luminosity relation
• Double Detonations with Thin, Modestly Enriched Helium Layers Can Make Normal Type Ia Supernovae
• Nebular spectra and abundance tomography of the type Ia supernova SN 2011fe: a normal SN Ia with a stable Fe core
• Nebular Spectra and Explosion Asymmetry of Type Ia Supernovae
• The resolved stellar populations in the LEGUS galaxies
• Type Ia Supernovae with Bi-Modal Explosions Are Common -- Possible Smoking Gun for Direct Collisions of White-Dwarfs
• Multi-dimensional simulations of radiative transfer in Type Ia supernovae
• Double detonations of sub-Chandrasekhar mass CO white dwarfs: Can different core and He shell masses explain variations of Type Ia supernovae?
• Non-Local Thermodynamic Equilibrium Radiative Transfer Simulations of Sub-Chandrasekhar-Mass White Dwarf Detonations
• Sensitivity study of explosive nucleosynthesis in Type Ia supernovae: I. Modification of individual thermonuclear reaction rates
• Critical ingredients of supernova Ia radiative-transfer modeling
• Three-dimensional simulations of gravitationally confined detonations compared to observations of SN 1991T
• Nucleosynthesis in thermonuclear supernovae
• Atomic data from the Iron Project. LXIV. Radiative transition rates and collision strengths for Ca II
• Monte Carlo radiative transfer for the nebular phase of Type Ia supernovae
• Thermonuclear Supernovae: Probing Magnetic Fields by Late-Time IR Line Profiles
• Mid-IR Spectra of Type Ia SN 2014J in M82 Spanning the First Four Months
• Non-thermal excitation and ionization in supernovae
• Including All the Lines
• Spectral modeling of type II supernovae II. A machine learning approach to quantitative spectroscopic analysis
• A JWST Near- and Mid-Infrared Nebular Spectrum of the Type Ia Supernova 2021aefx
• A Speed Bump: SN 2021aefx Shows that Doppler Shift Alone can Explain Early-Excess Blue Flux in Some Type Ia Supernovae
• Stable nickel production in Type Ia supernovae: A smoking gun for the progenitor mass?
• Towards Nebular Spectral Modeling of Magnetar-Powered Supernovae
• JWST Low-Resolution MIRI Spectral Observations of SN~2021aefx: High-density Burning in a Type Ia Supernova
• Understanding nebular spectra of Type Ia supernovae
• Models of pulsationally assisted gravitationally confined detonations with different ignition conditions
• Radiative Transition Properties of Singly Charged Magnesium, Calcium, Strontium and Barium Ions
• Modelling the ionisation state of Type Ia supernovae in the nebular-phase
• The intermediate nebular phase of SN 2014J: onset of clumping as the source of recombination
• Collision strengths and transition probabilities for Co II infrared forbidden lines
• Collision strengths and transition probabilities for Co III forbidden lines
• The Atomic Physics Underlying the Spectroscopic Analysis of Massive Stars and Supernovae
• Spectroscopic diagnostics of low-ionized iron-peak elements. Electron-impact excitation of Ni${}^{3+}$ and photoionisation of Ni${}^{2+}$
• Energy levels and radiative rates for transitions in Fe V, Co VI and Ni VII
• The accuracy of post-processing nucleosynthesis
• Collisional- and photo-excitations of Ca IV including strong 3.2 $\mu$m emission line

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