Featured Image: Deep Imaging of a Radio Relic

composite radio and x-ray image of abell 2256

New radio observations from uGMRT (red) highlight the detailed structure of the radio relic that curves around the diffuse X-ray emission seen by the Chandra X-ray Observatory (blue). Various regions of the radio relic are labeled. Click for high-resolution version. [Rajpurohit et al. 2022]

Galaxy cluster Abell 2256 is home to an incredible variety of structures traced by radio emission. The most prominent structure is an extended radio relic: a region of diffuse radio emission found on the outskirts of a cluster of galaxies. The precise cause of these massive radio relics is unknown, though shocks are expected to play a central role; the acceleration, re-acceleration, or compression of plasma by a shock wave could all cause the observed emission. Using new deep observations by the Giant Metrewave Radio Telescope (uGMRT) — shown above and to the right — a team led by Kamlesh Rajpurohit (University of Bologna, Italy; National Institute of Astrophysics, Italy; Thuringian State Observatory, Germany) investigated the cause of the striking radio emission surrounding Abell 2256. The new high-resolution images and spectra suggest that the surface of the radio relic traces a shock front, which is jumbled and twisted by interactions with the hot, turbulent plasma that suffuses the space between the galaxies in the cluster. For more fantastic images of the Abell 2256 radio relic, be sure to read the full article below!


“Deep Low-frequency Radio Observations of A2256. I. The Filamentary Radio Relic,” K. Rajpurohit et al 2022 ApJ 927 80. doi:10.3847/1538-4357/ac4708