SDSS Unveils 3.3 Million Spectra in DR20, Expanding Black Hole Map 4-Fold
Updated
Updated · Open Access Government · Aug 4
SDSS Unveils 3.3 Million Spectra in DR20, Expanding Black Hole Map 4-Fold
3 articles · Updated · Open Access Government · Aug 4
Summary
DR20 adds the first public BOSS spectra from Chile’s Las Campanas Observatory, giving SDSS-V an all-sky spectroscopic view when combined with Apache Point operations in New Mexico.
The release contains more than 3.3 million optical spectra across 500,000 galaxies and 1.5 million stars, while the Black Hole Mapper portion grew three to four times to about 1.1 million spectra of 500,000 objects.
SPIDERS links SDSS spectroscopy with eROSITA sky maps to identify and measure distances for roughly 200,000 X-ray targets—the largest uniform follow-up of X-ray sources yet assembled.
Those combined data show an unexpectedly high density of very bright active galactic nuclei near redshift 6, suggesting giant black holes were already growing rapidly during cosmic dawn.
Calculations also indicate only a small share of local black hole mass comes from soft X-ray-selected objects, implying 70% to 90% of total growth was obscured by gas and dust or X-ray suppressed.