| 11th of October 2023 |
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| ASKAP and eROSITA surveys of galaxy clusters |
| by Böckmann et al. |
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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. |