Scientists publish unique pictures taken from exploded Japanese telescope Hitomi

A collaboration of astrophysicists working with the lost Japanese astronomy satellite Hitomi has published the first and the last pictures taken by this X-ray observatory just before the catastrophe on board, as it is said in an article published in the Nature journal.

The Japanese satellite Hitomi, the sixth X-ray observatory of Japan, was launched in mid-February 2016. The first month passed normally, but at the end of March, when researchers were conducting the last check before putting the observatory into operation, it suddenly ceased communicating with the Earth and, as NASA pictures showed, broke into pieces.

In the first days after the incident several times Hitomi showed signs of life, that kept alive the hope for his "resurrection", but in the following weeks experts from JAXA failed to restore communication with Hitomi and to understand what was happening with it, being confined to observations from the Earth. Eventually the mission was completed at the end of April.

Professor of the National Research Nuclear University MEPhI, the best Russian university in engineering education, Felix Aharonian and his colleagues from the Hitomi collaboration, including Andrew Fabian from Cambridge University (UK), presented the first and the last data received by the telescope during the test of its scientific instruments in late February and early March 2016, and also said that the observatory exploded due to a basic error—the wrong mathematical sign in the program that ran his engine. Failure occurred in a stabilization system spun Hitomi and destroyed it.

These unique photos show how gas is moving in the nucleus of a distant galaxy NGC 1275 in the Perseus constellation, revolving around a supermassive black hole at its center and around it in the intergalactic medium. A cluster of galaxies, where it is located, became the first and last object, in which scientists were able to trace the movement of gas directly, without using indirect methods of observation.

As Felix Aharonian and his colleagues noted, monitoring the flow of gas allowed astrophysicists to see for the first time how black holes inhibit the cooling of the hot hydrogen clouds in galaxies and beyond them, and thereby "suffocat" star formation processes in it, turning them into a giant graveyard of stars.

Hitomi made relatively unexpected discovery: the gas between galaxies is moving relatively slowly, its speed does not exceed 150 km per second. These results should be of interest to cosmologists trying to understand what dark matter and its more mysterious cousin, dark energy is.

In addition, gas observations helped scientists to calculate the exact mass of all clusters of galaxies in the Perseus constellation – it was almost the same as estimated values that were calculated by data collected by other x-ray telescopes, which track not turbulence of gas but its intensity. It means that other types of observations do not strongly distort estimates of masses, and that they can be used in cosmological studies.

This is, apparently, where the scientific contribution of the Hitomi mission ends – the telescope simply did not have time to transfer other useful information to the Earth. Its closest analogues – for example, a European telescope Athena won't be launched very soon: in 2028 in the best case scenario, and therefore the mysteries of black holes and their impact on lives of galaxies will still remain unexplored in X-rays. According to Andrew Fabian, several space agencies are now trying to find resources to build a substitution for Hitomi, which could mean the launch of its successor in the next 4-5 years, not 12 years later like "Athena".

More information:
AVBalakireva@mephi.ru

Provided by National Research Nuclear University