Astronomers unveiled on January 31 "the largest and most detailed X-ray map of the universe ever created". The data comprises an X-ray view of half the entire sky over Earth, involving almost a million high-energy cosmic sources. These include over 700,000 supermassive black holes.
"The first eRosita All-Sky Survey Catalogue (eRASS1) is the largest collection of X-ray sources ever published, with around 9,00,000 individual sources," a research organisation based in Germany said in a report.
The first sky-survey data was collected by the soft eRosita X-ray imaging telescope flying aboard the Spectrum-RG (SRG) satellite. This catalog has been dubbed the "eROSITA All-Sky Survey Catalogue (eRASS1)".
The work was published in the journal Astronomy & Astrophysics. The catalogues presented form part of the first data release (DR1) of the SRG/eROSITA all-sky survey.
Check here detailed 'X-ray image of half the sky'
The eROSITA telescope began surveying the sky in December 2019, "with the aim of producing all-sky X-ray source lists and sky maps of an unprecedented depth", the research paper said.
It added that nearly 930,000 entries (of X-ray sources) were detected. The telescope detected 170 million X-ray photons - a record number.
The astronomers presented catalogues of both point-like and extended sources using the data acquired in the first six months of survey operations over the half sky "whose proprietary data rights lie with the German eROSITA Consortium".
According to a statement from the Max Planck Society in Germany, the 9,00,000 sources include around 7,10,000 supermassive black holes in distant galaxies (active galactic nuclei), "180,000 X-ray emitting stars in our own Milky Way, 12,000 clusters of galaxies, plus a small number of other exotic classes of sources like X-ray emitting binary stars, supernova remnants, pulsars, and other objects".
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"These are mind-blowing numbers for X-ray astronomy," Andrea Merloni, eROSITA principal investigator and first author of the eROSITA catalogue paper, was quoted as saying.
She added, "We’ve detected more sources in 6 months than the big flagship missions XMM-Newton and Chandra have done in nearly 25 years of operation.”
The main catalogue presented in the paper "increases the number of known X-ray sources in the published literature by more than 60%". It also provides a comprehensive inventory of all classes of X-ray celestial objects, covering a wide range of physical processes.
