eROSITA's Second Data Release Catalog Delivering the Most Comprehensive High-Energy Census of the Cosmos to Date

eROSITA's second data release (DR2) delivers the most comprehensive high-energy census of the cosmos to date, combining data from three full-sky scans to identify over 1.9 million point-like sources and 64,000 extended sources, including galaxy clusters and supernova remnants. The catalog includes data from multiple sky passes conducted every six months to progressively increase depth and sensitivity, and it links X-ray sources to their counterparts at other wavelengths. This allows researchers to determine what these objects are, their positions on the cosmic distance ladder, and build well-defined samples on an unprecedented scale.

• DR2 combines data obtained over Spektr-RG's first 556 days of observations, which were stacked to capture more objects with fainter fluxes.
• The catalog also includes multi-wavelength information that connects detections with their most likely optical and infrared counterparts.
• From this data, the team concluded that about 88% of the identified sources are extragalactic, predominantly from the actively accreting supermassive black holes (SMBHs) at the center of galaxies beyond our own.
• This release coincides with the Sloan Digital Sky Survey's twentieth release (SDSS DR20), which includes considerable optical spectroscopy provided by eROSITA-DE's surveys.
• Combining the data has enabled one of the largest and most detailed studies of SMBHs to date, allowing researchers to construct 3D maps of active black holes and track their evolution over cosmic time.
• Said William Roster, the lead author of the corresponding study: "The most luminous black holes at high redshift are like needles in a haystack. Thanks to DR2, we found more needles than expected, suggesting that rapidly growing black holes were more abundant in the early Universe than previously thought."

AI-generated summary of the original article — see the source for the full story.