Modelling of SN2013dx associated with the low-redshift GRB130702A points to diversity in GRB/SN properties

TL;DR

This study models SN2013dx, associated with GRB130702A, revealing it has typical ejected mass but unusually low kinetic energy, indicating diversity in GRB/SN explosion properties.

Contribution

It provides detailed spectral modeling of SN2013dx, highlighting its atypically low kinetic energy compared to other GRB-associated supernovae.

Findings

SN2013dx has similar nickel mass to other GRB/SNe.

It exhibits significantly lower kinetic energy (~10^{52} erg).

The KE/Mej ratio is smaller, affecting spectral line width.

Abstract

The properties of the broad-lined type Ic supernova (SN) 2013dx, associated with the long gamma-ray burst GRB130702A at a redshift z = 0.145, are derived via spectral modelling. SN2013dx was similar in luminosity to other GRB/SNe, with a derived value of the mass of 56Nickel ejected in the explosion of ~0.4 Msun. However, its spectral properties suggest a smaller explosion kinetic energy. Radiation transport models were used to derive a plausible mass and density distribution of the SN ejecta in a one-dimensional approximation. While the mass ejected in the explosion that is obtained from the modelling (Mej ~ 9 Msun) is similar to that of all other well-studied GRB/SNe, the kinetic energy is significantly smaller (KE ~ 10^{52}erg). This leads to a smaller KE/Mej ratio, ~ 10^{51} erg/Msun, which is reflected in the narrower appearance of the spectral lines. While the low KE does not represent a problem for the scenario in which magnetar energy aids powering the explosion and the nucleosynthesis, it is nevertheless highly unusual. SNe Ic with similar KE have never been seen in coincidence with a GRB, and no well-observed GRB/SN has shown similarly low KE and KE/Mej.