Some of the hottest and most energetic phenomena in the universe shine brightly in X-ray. Studying that part of the electromagnetic spectrum is not an easy task but observatories in space have accomplished this feat over the last six decades. The latest, from eROSITA, is an absolutely breathtaking X-ray map of the entire sky.
The map is the deepest X-ray view of the Universe, observing over 1 million objects and single-handedly doubling the number of X-ray sources we knew about. The sources vary from nearby stars’ hot coronae to distant supermassive black holes in a feeding frenzy.
“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.”
eROSITA is part of the Spektr-RG observatory, a Russian-German collaboration to observe the sky at high energy. The other instrument on board is ART-XC, used to spot supermassive black holes emitting X-rays. The data will provide researchers with the ability to study cosmic objects in a wider range of wavelengths as well as insight into transient phenomena picked by the telescope.
"We were all eagerly awaiting the first all-sky map from eROSITA,” added Mara Salvato, the scientist at MPE who leads the effort to combine eROSITA observations with other telescopes across the electromagnetic spectrum. “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.”
The map was composed from 182 days of observations, equivalent to 165 GB of data collected by the seven cameras of eROSITA. And this is just the first of seven maps expected to be completed over the next 3.5 years.
“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,” Kirpal Nandra, head of the high-energy astrophysics group at MPE, explained. “This combination of sky area and depth is transformational. We are already sampling a cosmological volume of the hot Universe much larger than has been possible before. 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.”