Soria et al. have presented the results of a multi-band study of the nearby “grand-design”, face-on spiral galaxy NGC 7424 located a little over 10 Mpc from our Galaxy. Two ultraluminous X-ray sources, dubbed X-1 and X-2, are detected and studied in detail. Thanks to a more accurate astrometric solution (based on Australia Telescope Compact Array and Gaia data), the point-like optical counterpart of X-1, an isolated B8 supergiant, was able to be identified. In contrast, X-2 is in a star-forming region (about 100 pc × 150 pc), near young clusters and ionized gas. In addition, a strong, persistent radio source, with an optical counterpart by no X-ray counterpart is detected.

NGC 7424 was observed with the ATCA in April 2021 at 5.5 and 9.0 GHz while the array was in a 6 km configuration, providing the highest angular resolution imaging at these frequencies. The image above shows a Gemini-South GMOS image of NGC 7424 with Chandra/ACIS-S contours of the brightest X-ray sources (0.3–7 keV band) overplotted in green. The location of a strong, persistent radio source (R-1) is also labelled.