DR20 represents a massive operational expansion of the foundations laid in prior releases, scaling the survey's efforts by delivering the first optical (BOSS) SDSS-V spectra from the Southern Hemisphere. This significant milestone integrates full all-sky panoptic spectroscopy across both hemispheres, providing an unprecedented look at the stars, interstellar gas, and distant galaxies of the cosmos. DR20 itself includes part of the panoptic spectroscopic map that is planned for the actively ongoing SDSS-V survey.
Mapping the local and distant Universe is key to our understanding of the physical processes that govern the cosmos. With DR20, the survey deepens its transition into a new era of multi-wavelength, multi-epoch optical and infrared observations.
What is New in Data Release 20?
Data release 20 has something for everyone – catalogs of black holes, stars, interstellar gas, and, of course, beautiful visualizations and scientific tools to navigate this extraordinary dataset.
"DR20 represents an enormous leap in the scale of SDSS data products — today we release over three million spectra of stars and galaxies along with 18 value added catalogs," said Dr. Emily Griffith of University of Colorado Boulder, spokesperson for the SDSS-V collaboration. "It's the product of years of work by a dedicated, international team of astronomers. We're excited to share DR20 with the world and see what the community discovers with it."
First Southern Hemisphere BOSS Spectra: DR20 features the historic debut of SDSS-V stellar and extra-galactic optical spectra observed from the du Pont 2.5m Telescope at Las Campanas Observatory (LCO) in Chile, combined with updated observations from the Sloan Foundation 2.5m Telescope at Apache Point Observatory (APO).
eROSITA-SDSS-V Coordinated Observations: In a major multi-wavelength synergy, DR20 introduces the first massive data stream for the SPectroscopic IDentification of ERosita Sources (SPIDERS) program coordinated with the second release of the eROSITA X-ray All-Sky Survey ( eRASS DR2 ). It provides crucial identification and optical redshifts for hundreds of thousands of X-ray emitting active galactic nuclei (AGN), galaxy clusters, and active stars.
The Black Hole Mapper (BHM): This release marks a dramatic 3-to-4-fold expansion of BHM data over DR19, delivering approximately 1.1 million optical BOSS spectra for roughly 500,000 distinct objects. In addition to the aforementioned SPIDERS program, this also includes major data streams from the All-Quasar Multi-Epoch Spectroscopy (AQMES) program and the Reverberation Mapping (RM) program to track supermassive black hole dynamics over time.
The Milky Way Mapper (MWM): DR20 includes a substantial new collection of optical stellar targets. Across the BHM and MWM surveys, the dataset encompasses over 3 million total spectra capturing 1.5 million stars including the first carbon-enhanced metal-poor stars in the Magellanic Clouds and the first intermediate-mass stripped star – both long-sought keys to star formation.
The Local Volume Mapper (LVM): Scaling up from its single-tile preview in DR19, the LVM has released integral field spectroscopy maps of 6 distinct target regions spanning 169 tiles and 300,000 spectra. These data maps chronicle Galactic HII regions, planetary nebulae, and nearby galaxies at unparalleled spatial scales and provide an opportunity for the community to analyze some beloved nebulae like the Rosette and Orion in this new way.
The LVMvis Visualization Tool: To complement the next-generation user interfaces (Zora and Valis) updated for this release, the collaboration has introduced LVMvis —an interactive, browser-based visualization tool that includes a stunning RGB HiPS emission-line map for exploring gas structures across the sky.
Expanded Value-Added Catalogs: Eighteen brand-new or comprehensively updated Value-Added Catalogs (VACs) have been integrated into DR20 to streamline specialized scientific research.
Accessing the Universe
As with all SDSS data releases, DR20 is fully cumulative. It includes all newly reduced BOSS spectroscopic data taken through February 2, 2025, from both hemispheres, combined with all spectroscopic data from all prior phases of the Sloan Digital Sky Survey.
The complete dataset is hosted on the Science Archive Server (SAS) , and an updated suite of Python Notebook Tutorials running server-side within SciServer Compute are now openly available to the global astronomical community and the public under open-use principles.
"We want everyone to make use of the SDSS data products, whether they are a professional astronomer doing their research, a student learning how to work with data, a teacher looking for classroom material, or someone who is just interested in astronomy in general," said Dr. Anne-Marie Weijmans of University of St Andrews, the SDSS Data Products Coordinator. "That is why we have so many different platforms for people to interact with the data, and we take care to provide numerous examples and tutorials for each of these. The data should not just be publicly available but be publicly usable."
"This data release provides some spectacular SDSS-V data that we are sure people will make excellent use of," said Dr. Juna Kollmeier of Carnegie Science, the SDSS-V Director. "But we aren't stopping here. We just spent a week talking about what will go into DR21 and DR22! We're going to need bigger computers!"
About the SDSS
Funding for the Sloan Digital Sky Survey V has been provided by the Alfred P. Sloan Foundation, the Heising-Simons Foundation, the National Science Foundation, and the Participating Institutions. SDSS acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. SDSS telescopes are located at Apache Point Observatory, funded by the Astrophysical Research Consortium and operated by New Mexico State University, and at Las Campanas Observatory, operated by the Carnegie Institution for Science. The SDSS web site is www.sdss.org .
SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration, including Caltech, the Carnegie Institution for Science, Chilean National Time Allocation Committee (CNTAC) ratified researchers, The Flatiron Institute, the Gotham Participation Group, Harvard University, Heidelberg University, The Johns Hopkins University, L'Ecole polytechnique fédérale de Lausanne (EPFL), Leibniz-Institut für Astrophysik Potsdam (AIP), Max-Planck-Institut für Astronomie (MPIA Heidelberg), Max-Planck-Institut für Extraterrestrische Physik (MPE), Nanjing University, National Astronomical Observatories of China (NAOC), New Mexico State University, The Ohio State University, Pennsylvania State University, Smithsonian Astrophysical Observatory, Space Telescope Science Institute (STScI), the Stellar Astrophysics Participation Group, Universidad Nacional Autónoma de México, University of Arizona, University of Colorado Boulder, University of Illinois at Urbana-Champaign, University of Toronto, University of Utah, University of Virginia, Yale University, and Yunnan University.
