The central regions of the cluster can be seen glowing brightly, with its diffuse outer regions extending outwards from the middle of the frame. Coma’s density is relatively even across its area, as reflected in the colouring (and thus brightness) of the different regions of this image, but rises gently towards the centre.
The overlaid blue and red arrows show the motion of the gas in the region (relative to the cluster itself), with blue arrows representing gas moving towards us, and red representing gas moving away. The length of the ‘tail’ on the arrows represents the size of the velocity: the longer the arrow tail, the faster the gas is moving.
This image is part of a new study of Coma and another nearly cluster, Perseus. The study spotted the first signs of gas sloshing around in Perseus – a behaviour that, while predicted, had never been seen before – while Coma appears to comprise two major sub-clusters that are slowly merging together.