On February 17, 2016, Japan launched a groundbreaking X-ray astronomy satellite, Hitomi (or Astro-H), which would have probed energetic events in the universe such as supermassive black holes. But a month later, disaster struck when it spun out of control. Ultimately, it was destroyed.
The destruction of the $273 million Hitomi satellite was a huge loss to astronomy. But, amazingly, in the month it was in orbit, it actually managed to complete some observations. And, in a new paper published today in Nature, we can see the fruits of those brief labors.
Before it died, Hitomi was able to gather data from the Perseus Cluster at the start of March for 2.5 days. Perseus is the brightest nearby cluster to Earth in X-rays, located about 240 million light-years away, with more than 1,000 galaxies. It was able to observe, for the first time, the process of a supermassive black hole stirring hot gas, at the heart of this galaxy cluster.
The results are surprising because they indicate that supermassive black holes can prevent the formation of stars by keeping this hot gas at a high temperature, in this case at about 50 million Kelvins. In turn, this may explain why galaxy clusters form fewer stars than expected.
Above, a montage of a Chandra X-ray image of Perseus (background) and the Hitomi X-ray readings. Hitomi Collaboration/JAXA, NASA, ESA, SRON, CSA
“It is surprising given that the observed region looks very disturbed,” study co-author Irina Zhuravleva, a postdoctoral researcher at the Kavli Institute for Particle Astrophysics and Cosmology (a joint SLAC-Stanford institute) and Stanford University, told IFLScience. “Hitomi’s observations confirmed the presence of such motions which heat the gas and quench star formation.”
Galaxy clusters are abundant in gas, so it was thought they should have relatively high rates of star formation, but that is not always the case. Despite this stirring effect, the speed of motion of the gas was quite small at about 160 kilometers (100 miles) per second, much slower than thought.
The results of this observation are 30 times better than anything previous, including NASA’s Chandra X-ray observatory. But sadly, with the loss of Hitomi, it will likely not be until the end of the 2020s with the European Athena X-ray Observatory that we get data that can match it.