Telescope captures breathtaking new X-ray map of the sky

A Russian and German telescope has completed its first full sweep of the sky — and it's provided some breathtaking images to mark the occasion. A new map, roughly four times the depth of its predecessor, captures what the universe looks like through X-ray vision. 

The eROSITA X-ray telescope, mounted on the space observatory Spektr-RG, launched last July, and finally reached its final position more than 900 million miles from Earth in December, according to a news release. It then spent 182 days slowly rotating, capturing the universe's mysterious dark energy with seven cameras.

A team of researchers at the Max Planck Institute for Extraterrestrial Physics in Germany said the resulting composite images show the deepest X-ray view of the sky we've ever seen. 

"This all-sky image completely changes the way we look at the energetic universe," Peter Predehl, the Principal Investigator of eROSITA, said in the release. "We see such a wealth of detail — the beauty of the images is really stunning."

The new map of the hot, energetic universe holds more than one million objects that emit X-rays —also known as X-ray sources — about 10 times more than what was found by the last all-sky sweep 30 years ago, the release said. The map roughly doubles the number of known X-ray sources, yielding about as many as have been discovered by all past X-ray telescopes in the field's 60-year history. 

Scientists said putting together the image was a "mammoth" task that required sorting through 165 GB of data. 

They generated the image using the so-called Aitoff projection, projecting the entire sky onto an ellipse with the Milky Way running horizontally through the middle and color-coding photons according to their energy, according to the release. Clusters of galaxies, "stellar cemeteries" made up of supernova remnants, and gas so hot it appears to glow can all be seen in the image. 

Nearly 80% of the image is made up of active galactic nuclei — supermassive black holes actively gobbling up material at the center of galaxies, the researchers said. In total, about one million X-ray sources were detected, "a treasure trove that will keep the teams busy for the coming years."

While scientists attempt to deepen their understanding of the development of the universe, the telescope is now sweeping the sky for the second time. 

The project, which will run for four years, aims to map the positions of millions of galaxies and gain insight into how the universe is structured, according to the release. The project may also help to unravel the mystery of dark energy and how it counteracts gravity, pushing matter apart to accelerate the expansion of the universe. 

"Overall, during the next 3.5 years, we plan to get seven maps similar to the one seen in this beautiful image," said Rashid Sunyaev, lead scientist of the Russian SRG team. "Their combined sensitivity will be a factor of five better and will be used by astrophysicists and cosmologists for decades."

"With a million sources in just six months, eROSITA has already revolutionized X-ray astronomy, but this is just a taste of what's to come," added Kirpal Nandra, head of the high-energy astrophysics group at MPE. "Over the next few years, we'll be able to probe even further, out to where the first giant cosmic structures and supermassive black holes were forming."