Galaxy clusters

Galaxy clusters are cool. Often introduced as the biggest objects in the Universe, they’re filled with gas, galaxies and dark matter. This is an image of Abell 2319, one of the clusters observed in the MENeaCS survey. Colours in the image are constructed from g and r observations. The image shows beautiful spiral galaxies (they should probably be bluer), saturated blue stars, yellow cluster member galaxies and the brightest cluster galaxy in the center.