Radio emission from Supernova Remnants

TL;DR

This paper reviews the current understanding of radio emissions from supernova remnants, focusing on their physical characteristics, evolution, and interactions with the surrounding medium, especially in the Milky Way and Magellanic Clouds.

Contribution

It provides a comprehensive overview of radio SNRs, including morphology, polarization, spectral analysis, and recent findings from the Magellanic Clouds, highlighting areas for future research.

Findings

Radio SNRs are key to understanding supernova explosion impacts.

Magellanic Clouds offer valuable insights due to spatial resolution.

SN 1987A serves as a prime example of real-time SNR evolution.

Abstract

The explosion of a supernova releases almost instantaneously about 10^51 ergs of mechanic energy, changing irreversibly the physical and chemical properties of large regions in the galaxies. The stellar ejecta, the nebula resulting from the powerful shock waves, and sometimes a compact stellar remnant, constitute a supernova remnant (SNR). They can radiate their energy across the whole electromagnetic spectrum, but the great majority are radio sources. Almost 70 years after the first detection of radio emission coming from a SNR, great progress has been achieved in the comprehension of their physical characteristics and evolution. We review the present knowledge of different aspects of radio remnants, focusing on sources of the Milky Way and the Magellanic Clouds, where the SNRs can be spatially resolved. We present a brief overview of theoretical background, analyze morphology and polarization properties, and review and critical discuss different methods applied to determine the radio spectrum and distances. The consequences of the interaction between the SNR shocks and the surrounding medium are examined, including the question of whether SNRs can trigger the formation of new stars. Cases of multispectral comparison are presented. A section is devoted to reviewing recent results of radio SNRs in the Magellanic Clouds, with particular emphasis on the radio properties of SN 1987A, an ideal laboratory to investigate dynamical evolution of an SNR in near real time. The review concludes with a summary of issues on radio SNRs that deserve further study, and analyzing the prospects for future research with the latest generation radio telescopes.