Some fascinating detail has come to light regarding a bridge of hot gas that exists between 2 galaxy clusters. Their collision several hundred millions of years ago created the bridge. The system, labelled Abell 2384, consists of 2 galaxy clusters 1.2 million light years away from the Earth. Together, they contain mass of over 260 trillion times that of our Sun.
Galaxy clusters are large groups of galaxies, held together by gravity, and are the largest objects in the universe. There can be hundreds or thousands of galaxies in one cluster. On top of this, a cluster contains extremely hot gas and large amounts of invisible dark matter.
Merging Galaxy Clusters
When the 2 clusters in Abell 2384 collided, they passed through each other, and left behind a trail of hot gas that now connects them. In addition, a nearby black hole is distorting the shape of the bridge! The new study about this draws on data from ESA’s XMM-Newton and NASA’s Chandra observatories. Both of these use X-rays to observe and take images.
In the image above, X-ray data is shown in blue. In addition, radio data from the Giant Metrewave Radio Telescope in India is shown in pink/red. Overlayed optical data comes from the Digitzed Sky Survey. This view allowed for the detection of a jet of particles originating from the black hole in the centre of one of the galaxies. Unusually, this is not the largest galaxy in the vicinity. This jet is pushing against the six trillion Suns worth of mass contained within the gas bridge. As well as this, it’s even powerful enough to bend its shape.
Evidence from computer simulations suggest that clusters such as these oscillate when they collide, passing through each other several times before eventually merging into one large cluster.