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11th of October 2023
ASKAP and eROSITA surveys of galaxy clusters
by Böckmann et al.
The extended ROentgen Survey with an Imaging Telescope Array (eROSITA) telescope on board the Spectrum-RoentgenGamma (SRG) mission has completed the first eROSITA All-Sky Survey (eRASS:1), detecting ∼104 galaxy clusters at X-ray energies in the western Galactic hemisphere. At radio wavelengths, ASKAP Pilot Survey observations for the EMU team detected 220,000 sources in a 270 square degree field overlapping with eRASS:1. Böckmann et al. have used these two surveys to study radio-mode active galactic nuclei in clusters. In order to understand the efficiency of radio-mode feedback at the centers of galaxy clusters, the team have related the radio properties of the brightest cluster galaxies to the X-ray properties of the host clusters, finding a statistically significant correlation between the X-ray luminosity of the cluster and the 944 MHz radio luminosity of the corresponding central radio galaxy. There is also a positive trend between the radio power and the largest linear size of the radio source. They find an anticorrelation between the central cooling time and the radio luminosity, indicating a need for more powerful active galactic nuclei in clusters with short central cooling times.

The image above shows a cutout of the nearby cluster J215129.7-552019 (RXC J2151.3-5521) at z = 0.03 clearly showing the radio jets that originate from the central radio source. The optical overlay makes use of legacy survey DS9 data, and the white circle is a measure of the cluster size.

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