Massive Cluster of Galaxies

Clusters of galaxies are concentrations of 100s to 1000s of galaxies, gravitational bound inside a dark matter halo. So much mass is contained within them, that they can gravitationally lensbackground objects. Most gas in clusters is so hot we detect it in X-rays.

The image shows the distribution of dark matter in a cluster of galaxies from EAGLE. In yellow are very dense concentrations of dark matter, which each will contain one or more galaxies.

The movie allows you to explore the three dimensional structure of the cluster, cycling

between dark matter, gas, and stars, as in the “Small Cluster” example. Note how there is a lot of red - very hot - gas. In EAGLE, as in the observations, the temperature of this gas is 10,000,000K - or comparable to that in the centre of the Sun! The gas is so hot because it is compressed by the gravity of the dark matter.