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SDSS DR20 Releases First Southern Hemisphere Optical Data, Maps Half Million Supermassive Black Holes
Key points
- SDSS DR20 includes first southern hemisphere optical BOSS spectra.
- The release maps about 500,000 supermassive black holes.
- SPIDERS project identifies 200,000 X-ray targets with optical spectroscopy.
- Data combines SDSS optical data with eROSITA X-ray sky maps.
SDSS DR20 Expands Black Hole Mapping
The Sloan Digital Sky Survey (SDSS) announced Data Release 20 (DR20), a significant expansion in the study of accreting supermassive black holes (SMBHs). This release is part of the fifth generation of the survey (SDSS-V) and its Black Hole Mapper (BHM) program, which focuses on understanding the masses, growth, and physics of quasars and active galactic nuclei (AGN).
New Southern Hemisphere Observations
DR20 incorporates the first optical BOSS spectra gathered from the southern hemisphere at Las Campanas Observatory (LCO) in Chile, complementing expanded observations from Apache Point Observatory (APO) in New Mexico. The release totals over 3.3 million optical spectra across 500,000 galaxies and 1.5 million stars, enabling multi-wavelength discoveries in conjunction with space-based observatories.
Unlocking High-Energy Universe with SPIDERS
A key component of the Black Hole Mapper in DR20 is the SPIDERS (SPectroscopic IDentification of ERosita Sources) project. SPIDERS combines SDSS optical spectroscopy with X-ray sky maps from the eROSITA mission to provide optical identifications and precise distance measurements (redshifts) for approximately 200,000 X-ray targets. This initiative represents the largest and most uniform spectroscopic follow-up of X-ray sources to date.
Mapping Cosmic Structure and Black Hole Demographics
While SPIDERS identifies tens of thousands of X-ray-emitting galaxy clusters and energetic star systems, the majority of these high-energy sources are actively accreting supermassive black holes, known as active galactic nuclei (AGN) or quasars. X-ray emission allows astronomers to observe the central regions of these black holes and their surrounding hot X-ray coronae. By measuring the X-ray luminosity function, scientists can track the growth of supermassive black holes across different power outputs and cosmic eras.
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Reporting from
The Sloan Digital Sky Survey (SDSS) released Data Release 20 (DR20), including the first optical observations from the southern hemisphere and coordinated X-ray identifications. This release provides an all-sky map of approximately 500,000 accreting supermassive black holes, advancing the study of quasars and active galactic nuclei.