# CHANG-ES XX. High Resolution Radio Continuum Images of Edge-on Galaxies and their AGNs -- Data Release 3

## TL;DR

This paper presents high-resolution radio continuum images and spectral index maps of 35 edge-on galaxies, revealing new features and AGN activity, and provides a data release for community use.

## Contribution

It offers the third data release of high-resolution radio images and spectral index maps, uncovering hidden structures and AGNs in edge-on galaxies, with implications for understanding galactic nuclei and disk emission.

## Key findings

- Detected hidden spiral arms in NGC 3448.
- Identified two new radio lobes near NGC 3628's nucleus.
- Found a 55% AGN detection rate based on radio criteria.

## Abstract

The CHANG-ES galaxy sample consists of 35 nearby edge-on galaxies that have been observed using the VLA at 1.6 GHz and 6.0 GHz. Here we present the 3rd data release of our sample, namely the B-configuration 1.6 GHz sample. In addition, we make available the {\it band-to-band} spectral index maps between 1.6 GHz and 6.0 GHz, the latter taken in the matching resolution C-configuration. The images can be downloaded from https://www.queensu.ca/changes. These are our highest resolution images ($\approx$ 3 arcsec) and we examine the possible presence of low luminosity active galactic nuclei in the sample as well as some in-disk structure. New features can be seen in the spectral index maps that are masked in the total intensity emission, including hidden spiral arms in NGC~3448 and two previously unknown radio lobes on either side of the nucleus of NGC~3628. Our AGN detection rate, using only radio criteria, is 55\% which we take as a lower limit because some weaker embedded AGNs are likely present which could be revealed at higher resolution. Archival XMM-Newton data were used to search for further fingerprints of the AGNs in the studied sample. In galaxy disks, discrete regions of flat spectral index are seen, likely due to a thermal emission fraction that is higher than the global average.