SN 1996cr: Confirmation of a Luminous Type IIn Supernova in the Circinus Galaxy

TL;DR

SN 1996cr is confirmed as a luminous Type IIn supernova in the Circinus galaxy, with extensive multi-wavelength archival data revealing its brightness and potential association with a gamma-ray burst, offering insights into supernova and GRB connections.

Contribution

This study confirms SN 1996cr as a Type IIn supernova and explores its possible link to a gamma-ray burst, using archival optical, X-ray, and radio observations.

Findings

SN 1996cr is among the brightest X-ray and radio supernovae.

It is potentially associated with GRB 4B 960202 at 2-3 sigma confidence.

SN 1996cr may be an off-axis or failed gamma-ray burst.

Abstract

We have recently confirmed SN 1996cr as a late-time type IIn supernova (SN) via VLT spectroscopy and isolated its explosion date to ~1 yr using archival optical imaging. We briefly touch upon here the wealth of optical, X-ray, and radio archival observations available for this enigmatic source. Due to its relative proximity (3.8 +/-0.6 Mpc), SN 1996cr ranks among the brightest X-ray and radio SNe ever detected and, as such, may offer powerful insights into the structure and composition of type IIn SNe. We also find that SN 1996cr is matched to GRB 4B 960202 at a 2-3 sigma confidence level, making it perhaps the third GRB to be significantly associated with a type II SN. We speculate on whether SN 1996cr could be an off-axis or ``failed'' GRB.