PTF12gzk - A Rapidly Declining, High-Velocity Type Ic Radio Supernova

TL;DR

This paper reports on the discovery and analysis of a rapidly declining, high-velocity Type Ic supernova, highlighting its unique properties and the potential for future detections with improved radio observation capabilities.

Contribution

It presents detailed radio and X-ray observations of PTF12gzk, revealing its high ejecta velocity and low circumstellar density, and discusses implications for supernova detection and progenitor understanding.

Findings

Ejecta velocity approximately 0.3c

Radio emission declined within 10 days

Circumstellar density lower by a factor of ~10

Abstract

Only a few cases of type Ic supernovae (SNe) with high-velocity ejecta have been discovered and studied. Here we present our analysis of radio and X-ray observations of a Type Ic SN, PTF12gzk. The radio emission rapidly declined less than 10 days after explosion, suggesting SN ejecta expanding at high velocity (~0.3c). The radio data also indicate that the density of the circumstellar material (CSM) around the supernova is lower by a factor of ~10 than the CSM around normal Type Ic SNe. Our observations of this rapidly declining radio SN at a distance of 58 Mpc demonstrates the potential to detect many additional radio SNe, given the new capabilities of the VLA (improved sensitivity and dynamic scheduling), that are currently missed, leading to a biased view of radio SNe Ic. Early optical discovery followed by rapid radio observations would provide a full description of the ejecta velocity distribution and CSM densities around stripped massive star explosions, as well as strong clues about the nature of their progenitor stars.