Astronomers have identified the Champagne Cluster, a merging of two galaxy clusters discovered on New Year's Eve 2020. The system's bubbly appearance and superheated gas earned it its festive nickname. This rare event provides insights into dark matter behavior during cosmic collisions.
The Champagne Cluster, formally known as RM J130558.9+263048.4, was first spotted by astronomers on December 31, 2020. Its nickname derives from the discovery date and the frothy look created by superheated gas, captured in purple hues by NASA's Chandra X-ray Observatory. Optical data from the Legacy Surveys, using telescopes in Arizona and Chile, add red, green, and blue layers to the composite image, revealing a stretched structure of hot gas that defies the typical circular or oval shapes seen in stable clusters.
This is no ordinary galaxy cluster; it comprises two separate groups colliding and merging into a larger entity. The image shows two distinct concentrations of galaxies—one above the center and one below—marking the participants in this merger. Rotated 90 degrees clockwise for viewing, with north pointing right, the scene highlights the vertical elongation of the gas, heated to millions of degrees. The hot gas's mass surpasses that of the more than 100 galaxies combined, while dark matter constitutes an even greater portion of the total mass.
Similar to the well-known Bullet Cluster, the Champagne Cluster features an offset where the hot gas has slowed from the impact, separating from the most massive galaxies in each subgroup. Researchers compared observations to computer simulations, proposing two possible histories. One scenario involves an initial collision over two billion years ago, followed by separation and a current second impact driven by gravity. The alternative suggests a single clash about 400 million years ago, with the clusters now drifting apart.
A study detailing these findings, led by Faik Bouhrik, Rodrigo Stancioli, and David Wittman from the University of California, Davis, was published in The Astrophysical Journal in 2025. Further analysis of this system could illuminate how dark matter interacts in high-speed mergers, advancing our understanding of cosmic structure formation. NASA's Marshall Space Flight Center oversees the Chandra program, with operations managed from Massachusetts.