SDSS-V Data Finds Early-Universe Black Holes Far More Common, With 70%-90% Growth Hidden
Updated
Updated · The Universe. Space. Tech · Aug 5
SDSS-V Data Finds Early-Universe Black Holes Far More Common, With 70%-90% Growth Hidden
3 articles · Updated · The Universe. Space. Tech · Aug 5
Summary
A new SDSS-V data release shows bright active galactic nuclei were more common in the early universe than models predicted, tracing black holes out to redshift 6—when the universe was under 1 billion years old.
About 70% to 90% of supermassive black-hole mass growth appears to have occurred behind dense dust or in states emitting little X-ray radiation, leaving much of it missed by optical and ultraviolet surveys.
Roughly 200,000 high-energy sources were identified by matching eROSITA X-ray detections with optical spectra and redshifts, creating the largest homogeneous sample yet of active galactic nuclei.
Data Release 20 contains more than 3.3 million spectra, including first-time Southern Hemisphere coverage from Chile, while some unusual quasar spectra had to be reviewed manually because automated analysis failed.
The X-ray catalog was released on July 31, 2026, using observations completed before Germany halted eROSITA sky scans in February 2022 after Russia's invasion of Ukraine.