Three major observatories (Subaru, GBT and XMM-Newton) have joined their forces to observe the collision of a pair of galaxy clusters, HSC J023336-053022 (XLSSC 105), located four billion light years away. The spectacular image resulting from the data taken by the Subaru telescope in the visible, the Green Bank Telescope in radio and finally the X-ray satellite XMM-Newton (a space facility intensively used by the Astrophysical Department / AIM Laboratory of CEA Paris-Saclay in particular with its XMM-XXL program), shows that the violence of the shock heats the gas located between the clusters to more than 400 million degrees. It also allows indirect mapping of the dark matter present in the system. This was work was published in the September 2020 issue of the MNRAS journal.
See : the ESA press release
Composite image of the data taken by the three observatories in optical, radio and X-ray, each color providing its own set of information. The individual galaxies within the cluster appear in orange and the dark matter - which maps the location of the two sub clusters - in blue (via optical observations from Subaru). The hot and dense gas appears in green (XMM-Newton X-rays), while its external component, thinner and under high pressure, appears in red (radio from the Green Bank telescope in Virginia, USA). This gas, known as "intra cluster medium", fills the space between galaxies. Credits: Radio: GBT Green Bank Observatory/National Science Foundation (NSF); Optical: Subaru Telescope, National Astronomical Observatory of Japan/HSC-SSP collaboration; X-ray: European Space Agency (ESA)/XMM-Newton/XXL survey consortium.
Contact CEA: Marguerite Pierre
"Active gas features in three HSC-SSP CAMIRA clusters revealed by high angular resolution analysis of MUSTANG-2 SZE and XXL X-ray observations" Okabe et al, Monthly Notices of the Royal Astronomical Society, Sept. 2020, https://arxiv.org/abs/1911.09236
See also :
The XMM-XXL site at CEA
1Pascal, Pensées B.1 (Différence entre l’esprit de géométrie et l’esprit de finesse)