Ring in the New Year with the "Champagne Cluster," a distant galaxy cluster featured in a new image that combines data from NASA's Chandra X-ray Observatory and optical telescopes.

Astronomers first identified this galaxy cluster on Dec. 31, 2020. That date, along with the cluster's bubbly look and the superheated gas detected by Chandra (represented in purple), led researchers to give it the memorable nickname "Champagne Cluster" instead of its formal name, RM J130558.9+263048.4.

Two Galaxy Clusters Colliding and Merging

The composite view reveals that the Champagne Cluster is not a single cluster at all. It is two galaxy clusters merging into a larger structure. In most clusters, gas heated to millions of degrees appears roughly circular or slightly oval in images. Here, the hot gas stretches much more from top to bottom, a clue that two clusters are colliding. You can also see two concentrations of galaxies, one above the center and one below it, marking the two groups involved in the merger. (The image has been rotated clockwise by 90 degrees so that North points to the right.)

Hot Gas and Dark Matter Dominate the Mass

In this forming cluster, the mass of the hot gas exceeds the combined mass of all the hundred-plus galaxies. Beyond that, the clusters hold even larger quantities of dark matter, the invisible material believed to be spread throughout the universe.

Alongside the Chandra X-ray observations, the image includes optical measurements from the Legacy Surveys (red, green, and blue). The Legacy Surveys bring together three complementary surveys using multiple telescopes located in Arizona and Chile.

A Rare Merger Like the Bullet Cluster

The Champagne Cluster belongs to an uncommon category of merging galaxy clusters. This group includes the famous Bullet Cluster, where the hot gas in each cluster has slammed together and slowed down, creating a clear offset between the hot gas and the most massive galaxy in each cluster.

To understand what happened, astronomers compared the observations with computer simulations and proposed two scenarios. In one, the two clusters collided more than two billion years ago, moved apart, and were pulled back together by gravity, with a second collision now underway. In the other, the clusters experienced a single collision about 400 million years ago and are currently moving away from each other. Researchers say additional studies of the Champagne Cluster could help show how dark matter behaves during a high-speed collision.

Research Paper and Chandra Mission Operations

A study presenting these findings recently appeared in The Astrophysical Journal. The paper's authors are Faik Bouhrik, Rodrigo Stancioli, and David Wittman from the University of California, Davis.