Nebular spectroscopy of SN 2014J: Detection of stable nickel in near-infrared spectra

Abstract

We present near-infrared (NIR) spectroscopy of the nearby supernova 2014J obtained ∼450 d after explosion. We detect the [Ni II] 1.939 μm line in the spectra indicating the presence of stable 58Ni in the ejecta. The stable nickel is not centrally concentrated but rather distributed as the iron. The spectra are dominated by forbidden [Fe II] and [Co II] lines. We used lines, in the NIR spectra, arising from the same upper energy levels to place constraints on the extinction from host galaxy dust. We find that that our data are in agreement with the high AV and low RV found in earlier studies from data near maximum light. Using a 56Ni mass prior from near maximum light γ-ray observations, we find 0.053 ± 0.018 M⊙ of stable nickel to be present in the ejecta. We find that the iron group features are redshifted from the host galaxy rest frame by ∼600 km s−1.