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

TL;DR

This study presents near-infrared spectra of supernova 2014J, detecting stable nickel in the ejecta, and provides insights into the composition, dust extinction, and velocity shifts in the supernova remnant.

Contribution

First detection of stable nickel in SN 2014J's ejecta using near-infrared spectroscopy, revealing its distribution and properties.

Findings

Detection of [Ni II] 1.939 μm line indicating stable $^{58}$Ni

Estimated ~0.05 solar masses of stable nickel in ejecta

Iron group features are redshifted by ~600 km/s

Abstract

We present near infrared (NIR) spectroscopy of the nearby supernova 2014J obtained $\sim$450 d after explosion. We detect the [Ni II] 1.939 $\mu$m line in the spectra indicating the presence of stable $^{58}$Ni 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 use 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 $A_V$ and low $R_V$ found in earlier studies from data near maximum light. Using a $^{56}$Ni mass prior from near maximum light $\gamma$-ray observations, we find $\sim$0.05 M$_\odot$ 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 $\sim$600 km s$^{-1}$.