Using the new eROSITA X-ray telescope, scientists have created the deepest-sever view of the sky as seen in the X-ray wavelength.
The image was created over a period of six months, during which the space-based telescope constantly rotated to image most of the sky. Each part of the sky had an exposure of 150 to 200 seconds, allowing an accuracy of measurement of photons of between 2% and 6%. The data was turned into a color-coded image to show the different energies of incoming photons.
The eROSITA telescope was launched last year, along with another X-ray telescope, ART-XC. ART-XC looks at high energy X-rays, while eROSITA looks at lower energy X-rays and is able to scan a huge area of the sky. That’s what allowed it to produce this extraordinary image.
“This all-sky image completely changes the way we look at the energetic universe,” Peter Predehl, the Principal Investigator of eROSITA at the Max Planck Institute for Extraterrestrial Physics (MPE), said in a statement. “We see such a wealth of detail — the beauty of the images is really stunning.”
The data for the image totaled more than 165 GB collected from seven cameras, which was put together to create this all-sky map. It pinpoints many new sources of X-rays, with a total of around one million objects, including objects such as supernova remnants, binary stars containing neutron stars, and black holes.
One such object which is close to Earth in relative terms and therefore a very bright source of X-rays is the beautiful Vela supernova remnant, a cloud of dust and gas left over from the explosion of a star 800 light-years away approximately 12,000 years ago.
The value of the data isn’t just for its own sake though. It can only be combined with data from other sources in other wavelengths such as visible light or infrared to help scientists see more of the sky.
“We were all eagerly awaiting the first all-sky map from eROSITA,” said Mara Salvato, one of the scientists who worked on combining the eROSITA observations with data from other telescopes. “Large sky areas have already been covered at many other wavelengths, and now we have the X-ray data to match. We need these other surveys to identify the X-ray sources and understand their nature.”
