【Today's XRISM】 20240802

XRISM is currently observing the galaxy cluster Abell 2029, located in the Virgo constellation.
A galaxy cluster is a celestial object formed by the strong gravitational pull of mysterious dark matter, which attracts hundreds of galaxies. The dark matter also gravitationally bind hot plasma (ionized gas). It is known that Abell 2029 contains an extremely hot plasma with a temperature of 80 million degrees Celsius.

XRISM is observing this hot plasma to accurately measure the pressure caused by both its thermal motion and turbulent motion. Since this pressure balances with the gravitational pull of the dark matter, the observation allows us to indirectly determine the distribution of the invisible dark matter.

Abell 2029 in X-ray (left) and optical (right)
Credits: X-ray: NASA/CXC/UCI/A.Lewis et al.; Optical: Pal.Obs. DSS