Observations of Type Ia Supernova 2014J with FLITECAM/SOFIA

TL;DR

This paper presents near-infrared spectra of SN 2014J obtained with SOFIA, revealing emission features and comparing them with models, highlighting the potential of airborne observatories for supernova research.

Contribution

First ~3 micron spectra of a SN Ia published, with detailed comparison to models, emphasizing the importance of airborne telescopes for NIR supernova observations.

Findings

Identification of ~1.77 micron emission as Co II blend

Spectra match models well in 1.5-2.7 micron range

Highlights the usefulness of SOFIA for inaccessible wavelength regions

Abstract

We present medium resolution near-infrared (NIR) spectra, covering 1.1 to 3.4 microns, of the normal Type Ia supernova (SN Ia) SN 2014J in M82 obtained with the FLITECAM instrument aboard SOFIA approximately 17-25 days after maximum B light. Our 2.8-3.4 micron spectra may be the first ~3 micron spectra of a SN Ia ever published. The spectra spanning the 1.5-2.7 micron range are characterized by a strong emission feature at ~1.77 microns with a full width at half maximum of ~11,000-13,000 km/s. We compare the observed FLITECAM spectra to the recent non-LTE delayed detonation models of Dessart et al. (2014) and find that the models agree with the spectra remarkably well in the 1.5-2.7 micron wavelength range. Based on this comparison we identify the ~1.77 micron emission peak as a blend of permitted lines of Co II. Other features seen in the 2.0 - 2.5 micron spectra are also identified as emission from permitted transitions of Co II. However, the models are not as successful at reproducing the spectra in the 1.1 - 1.4 micron range or between 2.8 and 3.4 microns. These observations demonstrate the promise of SOFIA by allowing access to wavelength regions inaccessible from the ground, and serve to draw attention to the usefulness of the regions between the standard ground-based NIR passbands for constraining SN models.