The Hitomi spacecraft was designed to discover the presence of black holes, but the vehicle malfunctioned soon after launch. The Japanese-designed space-based observatory was unable to complete its primary mission, but mission engineers now know what the spacecraft saw just prior to its untimely demise.
The Perseus Cluster is a tremendous grouping of thousands of galaxies, stretching 2 million light-years across, making it one of the massive objects seen anywhere in the observable Universe. Data recovered from Hitomi show a surprising discovery concerning this body.
The gas within the center of the cluster was seen traveling significantly slower than astronomers had predicted. Despite this lack of energy, the center of the cluster is home to a massive black hole, which normally would add to the total kinetic motion within such a structure — astronomers think this is puzzling.
"You'd expect the gas in this region to be quite stirred up, but it's not. It's really kind of quiet compared to how much disorder we see coming from the black hole," said Eric Miller from the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology (MIT).
Hitomi, developed by the Japanese space agency JAXA and NASA, was launched into space in February. The X-ray observatory was designed to record some of the most powerful events in the universe. The spacecraft would have examined galaxy clusters, supermassive black holes, and stars as they underwent explosive deaths. These highly energetic events result in the emission of vast amounts of X-rays, which can be detected by satellites orbiting Earth.
The Perseus Cluster, the first scheduled target for Hitomi, sits 250 million light-years from our own world. For roughly one month, the vehicle recorded X-rays from the galaxy cluster. The presence of iron and hydrogen was recorded within the massive structure. These observations can provide astronomers with the data they need to determine the average temperature within such a cosmic structure.
Following its brief foray studying the cluster, the spacecraft began to tumble out of control. Solar panels, which were the only source of power for the spacecraft, were jettisoned as the vehicle somersaulted out of control, dooming the mission. Soon after, controllers lost contact with the observatory. Hitomi was designed to operate for three years as it studied some of the most energetic events in the universe. Efforts to salvage the mission were called off on April 28.
Analysis of the data recorded by the Hitomi spacecraft before the loss of the vehicle was detailed in the journal Nature.