The Perseus signal is one of the most mysterious facts in the history of astronomy. A group of researchers gathered to investigate the Perseus cluster, a conglomerate of galaxies located about 250 million light-years from our solar system.
I could not believe my eyes, said Estra Bulbul from the Harvard Astrophysics Center in July 2014.
The Perseus cluster is one of the most massive objects known in the universe. According to the researchers, the cluster itself is wrapped in a vast atmosphere consisting of plasma. However, the mystery does not end there.
In the atmosphere of clusters, there are many ions, such as Fe XXV, Si XIV and S XV. Each of them produces a shock or line in the X-ray spectrum, which we can display with the help of Chandra, explains Bulbul. These spectral lines are in well-known x-ray energies. However, in 2012, when Bulbul combined the Chandra data in 17 days, a new line appeared, where no line should be. The line appeared at 3.56 keV (kiloelectronvolt), which does not correspond to any known atomic transition, she said. It was a big surprise.
Bulbul and her colleagues were fascinated and at first could not believe.
Speaking of Perseus clusters, Bulbul said: “It took a long time to convince ourselves that this line is neither an artifact of the detector nor a known atomic line.
I made very careful checks. I re-analyzed the data; He broke the data set into different subgroups and checked the data of four other detectors on board two separate observatories. None of these efforts led to the disappearance of the line.
Everything indicated that the discovery was reliable. This was further confirmed when Bulbul and her colleagues discovered an almost identical spectral signature in X-ray radiation originating from 73 other clusters of galaxies. Information was taken using the new X-ray telescope Europex XMM-Newton.
Soon after Bulbul and her colleagues published a study on the Internet, a team of scientists led by Alexei Boyarsky from the University of Leiden in the Netherlands presented evidence of the same spectral line in the observations of the Andromeda galaxy made by the XMM-Newton X-ray telescope.
In short, the spectral line seen by scientists does not come from any known type of matter, which ultimately removes suspicions that it could be caused by dark matter.
After we presented the article, theorists came up with about 60 different dark types of matter that could explain this line. Some particle physicists jokingly called this particle a remote control, and she laughed.
Further observations and research, of course, must be carried out in the future to understand one of the many mysteries of our universe.
To understand this, the Japanese space agency launched an advanced X-ray telescope called Astro-H. What can help astronomers in their search for answers?