An immense congregation of galaxies, designated RM J130558.9+263048.4, was identified by celestial observers on December 31, 2020. This particular date, coupled with the cluster’s bulbous morphology and the presence of intensely heated gas, prompted the researchers to bestow upon it the appellation “Champagne Cluster.” The recently synthesized composite visualization of this celestial grouping incorporates X-ray emissions captured by NASA’s Chandra X-ray Observatory alongside optical data procured from the Legacy Surveys.
The Champagne Cluster appears here as a large collection of brilliant white lights, each a distinct galaxy. A neon purple cloud stretches across the cluster’s crowded core. Many of the hundred-plus galaxies in the cluster are in two clumps of galaxies towards the top and bottom of center. Some are encircled by a faint glowing haze, while a few foreground stars gleam with diffraction spikes. Some of the smaller galaxies are tinted blue, orange, or red, and some appear more oblong than round, suggesting spiral shapes viewed edge-on. The neon purple cloud sits at the heart of the image, surrounding the most densely-packed part of the cluster. This cloud, which spreads vertically across the cluster, is multimillion-degree gas observed by Chandra. The two clumps of observable galaxies, and the spread of superheated gas, reveal that the Champagne Cluster is in fact two clusters in the process of colliding. Image credit: NASA / CXC / UCDavis / Bouhrik et al. / Legacy Survey / DECaLS / BASS / MzLS / SAO / P. Edmonds / L. Frattare.
Within a recent investigation, Faik Bouhrik, an astronomer affiliated with the University of California Davis, and his collaborators employed NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton observatory to conduct observations of the Champagne Cluster.
Furthermore, their analysis incorporated data that had been meticulously gathered utilizing the DEIMOS multiobject spectrograph at the W.M. Keck Observatory.
“The newly generated composite image substantiates that the Champagne Cluster is, in actuality, comprised of two galaxy clusters in the midst of coalescing to form an even more colossal cluster,” the scientific team conveyed in a formal statement.
“Typically, the multimillion-degree gas within galaxy clusters presents a roughly circular or moderately elliptical profile in imagery; however, within the Champagne Cluster, it exhibits a more extensive dispersion from its upper limit to its lower boundary, thereby signifying the presence of two colliding assemblages.”
“Two discernible aggregations of individual galaxies, which constitute the colliding clusters, are observable towards the central region, both above and below the midpoint.”
“The quantity of hot gas present exceeds the combined mass of all the more than one hundred individual galaxies within the nascent, forming cluster.”
“These clusters also contain substantially greater quantities of imperceptible dark matter, the enigmatic substance that permeates the entirety of the cosmos.”
The Champagne Cluster belongs to a scarce category of merging cluster systems, a classification that prominently includes the well-recognized Bullet Cluster. In such systems, the superheated gas originating from each constituent cluster has encountered resistance and decelerated, resulting in a pronounced demarcation between this heated gas and the most substantial galaxy within each respective cluster.
Through a comparative analysis of empirical data against sophisticated computational simulations, the research group formulated two distinct hypotheses regarding the evolutionary trajectory of the Champagne Cluster.
One plausible scenario posits that the two clusters experienced an initial collision more than two billion years in the past.
Subsequently to this initial impact, the two clusters are thought to have expanded outward before being drawn back towards one another by gravitational forces, and are presently on a trajectory for a secondary collision.
The alternative hypothesis suggests that a single collisional event transpired approximately 400 million years ago, and the two clusters are presently receding from each other in the aftermath of that encounter.
“Additional scholarly examinations of the Champagne Cluster hold the potential to illuminate our understanding of how dark matter interacts during high-velocity collisions,” the researchers stated.
Their comprehensive dissertation underwent peer review and was formally published in July 2025 within the esteemed pages of the Astrophysical Journal.
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Faik Bouhrik et al. 2025. Discovery and Multiwavelength Analysis of a New Dissociative Galaxy Cluster Merger: The Champagne Cluster. ApJ 988, 166; doi: 10.3847/1538-4357/ade67c
