Astronomers working with XMM-Newton have discovered a new cluster of galaxies, hidden behind a previously identified cluster of galaxies. The recently exposed cosmic giant is apparently just as bright as the first group, but is six times further away.
X-ray image of the area around the cluster Abell 3128 taken with XMM Newton. The bright spot on the left is hot gas in the recently discovered distant cluster, the spot on the right is hot gas in the cluster Abell 3128. Credits: ESA/ XMM/ EPIC/ SRON (N. Werner et al.)
The discovery was made by an international team using ESAs orbiting X-ray observatory. Being fooled by a cosmic giant is no laughing matter for an astronomer. For years, astronomers racked their brains over the relation between two regions equally bright and large in X-rays, located in the galaxy cluster known as Abell 3128.