Core collapse supernovae and starbursts

TL;DR

This paper reviews VLBI radio observations of core-collapse supernovae and starburst galaxies, highlighting how high-resolution radio imaging helps measure supernova and star formation rates independently of dust obscuration.

Contribution

It presents new high-resolution radio observations of (U)LIRGs, especially Arp 299-A, to directly detect CCSNe and determine star formation rates without relying on infrared luminosity models.

Findings

Direct imaging of CCSNe in nearby galaxies using VLBI.

Measurement of CCSN and star formation rates in (U)LIRGs.

Results from e-EVN observations of Arp 299-A.

Abstract

Core-collapse supernovae are the endproducts of massive stars, and yield radio events whose brightness depends on the intensity of the interaction experienced by the supernova ejecta with the circumstellar presupernova wind material. The fact that CCSNe are intrinsically radio supernovae --albeit with a huge range of different radio powers-- and hence unaffected by dust absorption, together with the high resolution and high sensitivity provided by current VLBI arrays, has been exploited to directly image the radio brightness structure of CCSNe in nearby (D <= 20 Mpc) galaxies. This has allowed to gain insight into the physics of both CCSNe and of the circumstellar medium (CSM) with which they interact. In addition, ultra-high-resolution, ultra-high-sensitivity radio observations of CCSNe in Luminous and Ultra-Luminous Infrared Galaxies (LIRGs and ULIRGs, respectively) in the local Universe, can be used to directly measure of the current CCSN rate and star formation rate. In this contribution, I give a brief overview of VLBI observations made of some CCSNe in nearby galaxies, and then present some of the most relevant results obtained with high-resolution radio observations of (U)LIRGs in the local Universe, aimed at directly detecting CCSNe via their radio emission, and thus determine their CCSN and star formation rates, independently of models. This is of particular relevance, in view of the fact that our estimates of star formation (and CCSN) rates in high-z starburst galaxies relies on standard relationships between far-infrared luminosity and star-formation rate. In particular, I will present recently obtained results with the e-EVN on the nuclear region of Arp 299-A.