DOI

https://doi.org/10.48717/91j8-1b69

Project

EL076

Title

High-resolution imaging of late-time radio rebrightening in SN 2022xxf

Abstract

SN2022xxf is an exceptional event: it is the most nearby type-Ic broad-lined supernova known so far (observed in NGC3705 at d ~ 13 Mpc), among the most radio luminous supernova ever detected, and is displaying a dramatic, second rebrightening episode more than 400 days post-discovery. The first rebrightening episode, seen in optical through to radio wavelengths, occurred from 50 to 100 days post-discovery, and was inferred to be due to the interaction of the supernova ejecta with a dense shell of circumstellar medium (CSM). Now after more than 400 days post-discovery, our new radio observations indicate the supernova is undergoing a second phase of rebrightening, with a clear spectral inversion. We request an additional epoch of EVN observations to help discern the nature of SN2022xxf, in particular, the origins of the second episode of rebrightening. We aim to distinguish between the two leading explanations for the rebrightening: (a) the interaction of the expanding supernova ejecta with a further dense CSM shell, expelled from the SN progenitor star years before its final explosion; or (b) emission from a large off-axis GRB afterglow, with the jet component emitting material entering now within our line of sight.