An Off-Axis Relativistic Jet Model for the Type Ic supernova SN 2007gr

TL;DR

This paper models SN 2007gr as a supernova with a weak off-axis relativistic jet, explaining radio and X-ray emissions while the optical light is from non-relativistic ejecta, fitting observed data with typical Wolf-Rayet star parameters.

Contribution

It introduces an off-axis relativistic jet model for SN 2007gr, linking observed emissions to a weak jet and providing a comprehensive fit to multiband observations.

Findings

Radio and X-ray emissions originate from the relativistic jet.

Optical emission is from decay of nickel-56 in the supernova ejecta.

The model fits observed multiband light curves well.

Abstract

We propose an off-axis relativistic jet model for the Type Ic supernova SN 2007gr. Most of the energy ($\sim2\times10^{51}$ erg) in the explosion is contained in non-relativistic ejecta which produces the supernova. The optical emission is coming from the decay process of $\rm ^{56}Ni$ synthesized in the bulk SN ejecta. Only very little energy ($\sim10^{48}$ erg) is contained in the relativistic jet with initial velocity about 0.94 times the speed of light. The radio and X-ray emission comes from this relativistic jet. With some typical parameters of a Wolf-Rayet star (progenitor of Type Ic SN), i.e., the mass loss rate $\dot{M}=1.0 \times10^{-5} M_{\odot} \rm yr^{-1}$ and the wind velocity $v_{\rm w}=1.5\times10^{3} \rm km s^{-1}$ together with an observing angle of $\theta_{\rm obs} = 63.3^{\circ}$, we can obtain the multiband light curves that fit the observations well. All the observed data are consistent with our model. Thus we conclude that SN 2007gr contains a weak relativistic jet and we are observing the jet from off-axis.