This galaxy cluster must be much, much colder than it actually is. Lingxiao Yuan
Recent discoveries about young galaxy clusters, such as SPT2349-56, are transforming our understanding of how these colossal structures formed and evolved in the early universe. Interestingly, the gas within SPT2349-56 is significantly hotter and denser than anticipated, posing intriguing questions for researchers.
Zhou Daizhi and their team at the University of British Columbia utilized the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to investigate this galaxy cluster. Their findings revealed that the gas at the cluster’s center reaches temperatures of tens of millions of degrees Celsius.
“The sun’s surface temperature is just a few thousand degrees Celsius, making this region much hotter,” Zhou notes. “Our conservative estimates indicate temperatures five to ten times higher than expected based on simulations, which is surprising since such hot gas was thought to exist only in clusters billions of years old.”
Located in the early universe, approximately 1.4 billion years after the Big Bang, SPT2349-56 is unlike any other known cluster of its age. Zhou explains, “This gas should still be relatively cold and in small quantities, as these nascent clusters are still in the process of accumulating gas and heating up.” However, SPT2349-56 seems to be more mature than anticipated.
The unusual heating could stem from the presence of particularly active galaxies within the cluster, with at least three galaxies emitting massive jets of energy. These jets, combined with intermittent star formation bursts, might be heating the gas rapidly, challenging previous assumptions.
“This discovery opens a new window into understanding stages of cluster evolution that we have not observed before,” Zhou emphasizes. The research team plans additional observations to locate more hot young clusters like SPT2349-56, with the hope of unraveling the complexities of galaxy formation.
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Source: www.newscientist.com
