The Sausage Cluster

The Sausage Cluster

Sidney_Hall_-_Urania's_Mirror_-_Lacerta,_Cygnus,_Lyra,_Vulpecula_and_AnserThe Sausage Cluster or CIZA J2242.8+5301 is located in the constellation Lacerta (the Lizard) in the Northern Hemisphere. It was first discovered by Kocevski et al (2007), as the second CIZA sample (a survey of clusters of galaxies behind the Milky Way. Its galactic coordinates places it very near the disk of the galaxy but away from the bulge, about 2.3 billion light-years from Earth.

sausage-merging-galaxy-cluster-compositeIts observation suggests that stagnant galaxies can be rejuvenated when huge clusters containing thousands of galaxies collide, like the Sausage cluster, which is also moving at a mind-boggling speed of 5.6 million mph (9 million km/h). But star formation at this rate leads to a lot of massive, short-lived stars coming into being, which explode as supernovae a few million years later, the study co-leader, David Sobral of Leiden Observatory and the University of Lisbon. The explosions drive huge amounts of gas out of the galaxies and with most of the rest consumed in star formation, the galaxies soon run out of fuel. They slip back into a coma and have little prospect of a second resurrection. The white circles indicate galaxies outside of the cluster, while yellow circles are cluster galaxies, where accelerated star formation is taking place. Green hues trace out shock waves and purple marks hot X-ray-emitting gas between the galaxies that emits X-rays. The next step is to see if the Sausage cluster is unique and that these bursts of star formation need very particular conditions. By studying a much bigger sample of galaxies, the team hope to find out exactly how they happen.

Credits: Royal Astronomical Society, Space.