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Understanding the vast scale of the universe is difficult for humans. Our brains evolved to process information about our immediate surroundings. We are not naturally equipped to grasp the complex dynamics of stars and galaxies. However, every once in a while, astronomers discover something that helps us comprehend the true size of the cosmos. A new study describes a rare event that illustrates this magnitude. The research details the merger of six supermassive galaxies. This event provides a unique window into the violent and dynamic nature of galactic evolution.
The new paper does not represent the first discovery of this galaxy cluster. That initial identification occurred in 2018. Several all-sky surveys contributed to this early finding. These included the Two Micron All Sky Survey, WISE, and SuperCOSMOS. However, these earlier surveys did not fully recognize the complexity of the cluster. The critical detail was hidden within data from the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys. This data revealed a group of six merging galaxies at the center of the cluster.
To confirm this finding, astronomers used powerful telescopes. They utilized the Mayall, Bok, and Blanco telescopes located in Arizona and Chile. These instruments allowed them to resolve the individual galaxies. They observed six massive galaxies merging into a single entity. Astronomers refer to this central object as the Brightest Cluster Galaxy. This term describes the brightest galaxy within a cluster of galaxies. It is typically the most massive and dominant galaxy in its group.
Surrounding this massive merging galaxy, the DESI survey detected a large shroud of light. This shroud spans 310 kiloparsecs. It is known as Intracluster Light, or ICL. This light appears as a glowing fog. It consists of stars that were stripped from their host galaxies. The violent dynamics of the merger ejected these stars into the space between galaxies. To see this afterglow effect, astronomers had to remove the bright light from the galaxies themselves. This process revealed the subtle glow of the merged system.