Hitomi spacecraft revealed valuable data before its premature doom. The X-ray space telescope observed emissions from a galaxy cluster and measured the speed of the movement of the interstellar gasses between the galaxies. It showed that it is not as fast as scientists expected.
On February 17th, the Japan Aerospace Exploration Agency (JAXA) launched the Hitomi satellite from the Tanegashima Space Center in Japan to search for black holes and supernovas across space. On March, the satellite started to fail, and engineers lost control of the spacecraft. On April, the agency finally declared it dead.
Image Credit: Akihiro Ikeshita/JAXA
Right before the spacecraft completely broke apart, it captured gas emissions from the Perseus galaxy cluster, which holds more than 1,000, and is located over 200 million light years away. It is the brightest and most massive X-ray cluster known.
Scientists studied the measures provided by the satellite and found that the gas between the galaxies moves at about 102 miles per second, which is way less turbulent than what they had expected.
The new findings could help understand why so few stars from within the cluster
The dense superheated gas that moves between galaxies churns at a speed of 366,858 miles per hour (164km/s), according to a study published Wednesday in Nature. This is much lower than what researchers expected, because, within the cluster, galaxies move a lot faster, at thousands of miles per second.
“I was expecting to see the gas tossed around a lot more,” said Brian McNamara, an astrophysicist at the University of Waterloo and a member of Hitomi’s science team to The Globe and Mail.
Hitomi spotted the stirring of hot gasses around the center of a supermassive black hole located inside NGC 1275, a galaxy near the center of Perseus. By churning the gas, the black hole has control over the formation of new stars because it keeps the material hot, at about 100 million degrees. When cooled down, new stars are born.
Andrew Fabian, director of the Institute of Astronomy at the University of Cambridge and part of the Hitomi’s team, told Space.com that without the activity provoked by the black hole, “the central galaxy would be much brighter and have a much higher stellar mass.”
Now researchers have a greater understanding of the role of supermassive black holes: they keep gas from cooling down by injecting energy into it, Norbert Werner, a research associate at Stanford University, said in a statement, according to Space.com.
Previously, scientist thought that the constant stirring of the gasses by supermassive black holes resulted in the generation of bubbles of hot plasma, and they prevented the gas from condensing and forming new stars. “Now we understand this mechanism better and see that there is just the right amount of stirring motion to produce enough heat,” Fabian added.
Hitomi could detect X-ray emissions because the gasses in clusters, besides being extremely hot, they also have a particular density. Collisions between particles of elements like hydrogen, helium, and iron, which mostly compose of the structure of the gas, are constantly happening, emitting X-rays.
These collisions and constant movement were thought to be aggressive and turbulent, but the study shows that it is not as chaotic as scientists assumed.
Another surprising aspect about Hitomi the study found is the amount of precision the satellite’s Soft X-ray Spectrometer had. Variations on the gas speed measured by Hitomi could be as low as 6 miles (10 kilometers) per second. “It demonstrates the potential of this kind of instrument,” Fabian told The Verge.
According to Fabian, this could lead to the fabrication of another Hitomi with the same characteristics. The satellite cost the agency about $273 million.
Source: Space.com