Optical and NIR observations of the nearby type Ia supernova SN 2014J

TL;DR

This paper presents comprehensive optical and near-infrared observations of the nearby Type Ia supernova SN 2014J, analyzing its light curves, spectra, ejecta properties, and polarization to understand its characteristics and classify its subtype.

Contribution

It provides detailed observational data and analysis of SN 2014J, including light curves, spectral features, ejecta mass, nickel mass, and polarization, offering insights into its classification and explosion properties.

Findings

SN 2014J has a decline rate parameter $ riangle m_{15}(B) = 1.08$.

Ejected mass is approximately 1.3 solar masses, with 0.6 solar masses of $^{56}$Ni.

Polarization is consistent with interstellar origin, indicating dust effects.

Abstract

Optical and NIR observations of the type Ia supernova SN 2014J in M82 are presented. The observed light curves are found to be similar to normal SNe Ia, with a decline rate parameter $\Delta m_{15}(B) = 1.08 \pm 0.03$. The supernova reached $B$-band maximum on JD 2456690.14, at an apparent magnitude $m_B(max) = 11.94$. The optical spectra show a red continuum with deep interstellar Na~{\sc i} absorption, but otherwise resemble those of normal SNe Ia. The Si~{\sc ii} $\lambda 6355$ feature indicates a velocity of $\sim 12\,000$ km s$^{-1}$ at $B$-band maximum, which places SN 2014J at the border of the Normal Velocity and High Velocity group of SNe Ia. The velocity evolution of SN 2014J places it in the Low Velocity Gradient subclass, whereas the equivalent widths of Si~{\sc ii} features near $B$-band maximum place it at the border of the Core Normal and Broad Line subclasses of SNe Ia. An analytic model fit to the bolometric light curve indicates that a total of $\sim 1.3$ M$_{\odot}$ was ejected in the explosion, and the ejected $^{56}$Ni mass $M_{Ni} \sim 0.6$ M$_{\odot}$. The low [Fe~{\sc iii}] $\lambda4701$ to [Fe~{\sc ii}] $\lambda5200$ ratio in the nebular spectra of SN 2014J hints towards clumpiness in the ejecta. Optical broadband, linear polarimetric observations of SN 2014J obtained on four epochs indicate an almost constant polarization ($P_{\rm R} \sim$2.7 per cent; $\theta$ $\sim$37$^\circ$), which suggests that the polarization signal is of interstellar origin.