Here is the last thing the satellite Hitomi saw before dying – L’Express

Hitomi was a satellite full of promise. Launched by the Japan Aerospace Exploration Agency (Jaxa) in February this year he had the task of pointing its instruments to black holes and discovering some of the best kept secrets of our universe.

But because of a series of technical and human error, the unfortunate machine is still operational five short weeks. If Japanese engineers have done everything to regain control -with the help of the NASA-, they had to admit late April that the satellite of € 248 million was lost forever. And with it a part of their technical credibility if not scientific.

Fortunately -for them and for science-, the Japanese researchers were able to recover some data just before the total loss of control Hitomi (meaning eye pupil, in Japanese). They have just published the results of their analysis in Nature .

We know for example that the last thing seen by the satellite before dying was the Perseus cluster -a grouping of galaxies located 250 million light years of the Earth whose center a supermassive black hole. Better, Hitomi was able to measure, through a spectrometer X-ray, the activity of this part of the universe.

the Perseus cluster seen with X-ray spectrometer, which allows to see the hot gases.

NASA

The researchers made two discoveries. The first is that, contrary to what they thought, the activity of the center of the cluster is quite low. “The hot gas inside the cluster is much slower and less chaotic than expected,” confirms Gizmodo co-author of the study Andrew Fabian of the University of Cambridge. The hot gases present between galaxies, traveling “only” 540 000 km / hour.

STORIES & gt; & gt; The black hole at the heart of the Milky Way with unprecedented precision observed

The second discovery follows from the first. For this new information on the hot gas of the Perseus cluster could partly explain the role of black holes in the formation and growth of galaxies.

See you in 2028

According to Brian McNamara, a researcher at the University of Waterloo, another co-author of the analysis, the data collected show that “black holes are largely responsible for the size of galaxies”, partly because they “control their growth very effectively.”

But in the end, the researchers do not know exactly “how it works in detail,” admits Mark Bautz, who also worked on the study published in Nature. One thing is certain, before Hitomi, “we had no idea or almost,” he adds.

An image of the Perseus Cluster of taken by the telescope of NASA Chandra superimposed with the information provided by Hitomi.

HITOMI COLLABORATION / JAXA, NASA, ESA, SRON, CSA

“These results show the potential of a satellite equipped with X-ray detector to transform our understanding of the universe, including exploring the hot gases, “said Andrew Fabian. This highlights both the lack of knowledge we have on the subject, and how Hitomi points could help.

Unfortunately, for more information, it will be patient and wait for 2028, when the European Space Agency (ESA) will launch a similar satellite Hitomi.