Classifying Compact Radio Emission in Nearby Galaxies: a 10GHz Study of Active Galactic Nuclei, Supernovae, Anomalous Microwave Emission and Star Forming Regions

TL;DR

This study uses high-resolution 10GHz radio observations of three nearby galaxies to identify and classify compact radio sources, revealing diverse objects including star-forming regions, AGN, supernova remnants, and anomalous microwave emission candidates.

Contribution

It provides a detailed catalog of compact radio sources in three galaxies at 10GHz, demonstrating the importance of high-resolution radio imaging for astrophysical studies.

Findings

Identified 115 compact radio sources across three galaxies.

Found multiple sources associated with star formation, AGN, and supernova remnants.

Highlighted the potential for future radio facilities to advance galaxy studies.

Abstract

We present 115 compact radio point sources in three galaxies, NGC 5474, NGC 4631 and M51, taken in the most extended (A-)configuration of the Karl G. Jansky Very Large Array at 10GHz. Several of these compact radio point sources have diffuse counterparts identified in previous multi-band studies of resolved radio continuum emission. We find compact counterparts to eight star forming regions, four anomalous microwave emission candidates, and one supernova remnant (SN 2011dh). Nine of the compact radio sources match X-ray counterparts, the majority of which are background galaxies. These AGN are all within the D25 (isophotal diameter) of the host galaxy and might act as contaminants for X-ray binary population studies, highlighting the need for high-resolution multi-band imaging. This study showcases the broad number of science cases that require sensitive radio facilities, like the upcoming Square Kilometre Array and the planned next generation Very Large Array.