The Perseus galaxy cluster is one of the most massive objects in the universe. It contains more than 1,000 galaxies, it’s located about 240 million light-years away and at its center, there’s a supermassive back whole. It caught scientists’ attention in 1970 when a high X-ray emission was detected during an Aerobee rocket flight. When observed in the X-ray band, the Perseus cluster is the brightest cluster in the sky.
What is a Galaxy Cluster?
A galaxy cluster is a structure that consists of hundreds to thousands of galaxies bound together by gravity. Clusters are closed systems meaning, they hold on to their gases, unlike galaxies where gas is forced out by supernova explosions. Gases in the Perseus galaxy clusters are constantly hot, leaving scientists with a puzzle. When vast amounts of hot gas in clusters cool down, it allows for the formation of a large number of stars.
In 2014, astronomers reported the detection of an unusual emission in the X-ray light from the center region of the Perseus cluster. Similar emissions were reported on 73 other galaxy clusters.
The specific wavelength of X-rays (3.5 keV) was detected in the region surrounding the supermassive black hole. Research showed this emission did not come from known elements, therefore, its hypothesized this emission was produced by dark matter particles. “This suggests that dark matter particles in the cluster are both absorbing and emitting X-rays.” Further research is still ongoing, and the research will help provide proof into the nature of dark matter.
On June 2017, a paper described the findings of a 200,000 light-year wave rolling through the Perseus galaxy cluster. Observations from NASA’s Chandra X-ray Observatory coupled with a computer simulation, show the gravitational disturbance resulting from the distant flyby of another galaxy cluster. The event causes cooler gas at the heart of the Perseus cluster to form a vast expanding spiral, which ultimately forms giant waves lasting hundreds of millions of years at its perimeter.
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