The new Sloan Digital Sky Survey release brings together more than three million spectra and, for the first time, includes optical spectra from SDSS-V obtained from the Southern Hemisphere with the du Pont Telescope at Las Campanas Observatory. The release also includes new data from the Local Volume Mapper, installed at LCO.
The Sloan Digital Sky Survey (SDSS) has published its twentieth data release, Data Release 20 (DR20), the third public release from its fifth phase, SDSS-V. The new dataset contains more than three million spectra of stars and galaxies and expands the survey’s coverage through observations carried out from both the Northern and Southern Hemispheres.
For Carnegie Science’s Las Campanas Observatory, this release marks another step in its participation in SDSS-V. DR20 includes, for the first time, publicly available BOSS optical spectroscopy obtained with the SDSS-V fiber positioning system installed on the 2.5-meter Irénée du Pont Telescope. These observations are the first optical spectra from this phase of the project obtained from the Southern Hemisphere to be included in a public SDSS data release.
The data obtained from Las Campanas complement observations made with the 2.5-meter Sloan Foundation Telescope at Apache Point Observatory in New Mexico. Operating facilities in both hemispheres allows SDSS-V to expand its sky coverage and study objects and regions that cannot be observed from a single site.
Some of these new spectra belong to the Milky Way Mapper and Black Hole Mapper, two of the major scientific programs within SDSS-V. Milky Way Mapper studies stellar properties and the structure of our Galaxy, while Black Hole Mapper observes, among other objects, quasars and active galactic nuclei to investigate the growth and properties of supermassive black holes. Observations for both programs combine data obtained from Apache Point and Las Campanas.
For Black Hole Mapper, DR20 includes approximately 1.1 million optical spectra corresponding to nearly 500,000 objects. The new release substantially expands the available coverage compared with the previous data release and, for the first time, includes public observations of the program in more southerly fields obtained from Las Campanas.
The twentieth data release also contains data from SDSS-V’s third major program, the Local Volume Mapper (LVM). Its instrument is installed at Las Campanas Observatory and uses integral-field spectroscopy to study the interstellar gas of the Milky Way, the Magellanic Clouds, and nearby galaxies. Rather than obtaining spectra only for individual objects, this technique provides spectroscopic information across entire regions of the sky, allowing researchers to study how their properties vary from one location to another.
DR20 considerably expands the publicly available LVM sample. While the previous release contained only an initial test region, this release includes 169 fields across six regions and approximately 300,000 spectra. The areas covered include star-forming regions such as the Orion and Rosette nebulae.
These observations make it possible to study how radiation and winds produced by young, massive stars interact with the surrounding gas. The spectroscopic maps contain information about the physical and chemical conditions of the interstellar medium and help researchers examine the processes that connect the formation of new stars with the evolution of gas within galaxies.
In addition to the new spectra, DR20 includes 18 new or updated scientific catalogs and tools for exploring the data. Among them is LVMvis, an interactive platform developed to visualize the spectroscopic maps produced by the Local Volume Mapper. As with previous Sloan Digital Sky Survey releases, the data are publicly available to the scientific community.
SDSS is an international collaboration that brings together researchers and institutions from different countries. In its fifth phase, observations carried out with the du Pont Telescope and the Local Volume Mapper at Las Campanas complement those obtained from Apache Point Observatory and allow SDSS-V programs to extend farther into the southern sky. SDSS-V Director Juna Kollmeier is an astronomer at Carnegie Science.
With DR20, the project makes another part of the spectroscopic map that SDSS-V continues to build available to the community. For Las Campanas, the release brings together two specific contributions from the observatory: the inclusion of the first publicly released SDSS-V optical spectra obtained from the Southern Hemisphere with the du Pont Telescope, and a new collection of Local Volume Mapper observations carried out from LCO.
Image: A three-part image showing results from the three mappers that make up DR20 data. Left and Background: The LVM RGB color visualization of the Great Orion Nebula. This zoom-in is a small portion of the HiPS map that is being released as a Value Added Product in DR20. Center: Sky distribution of DR20 astronomical objects targeted by the Black Hole Mapper (BHM) program in SDSS-V. Right: Density of stars in the Milky Way targeted by the Milky Way Mapper (MWM) program in SDSS-V
Image credits:
Left: SDSS-V, Ivan Katkov, New York University Abu Dhabi & Sebastian Sanchez, UNAM
Center: SDSS-V, Scott Anderson, University of Washington
Right: SDSS-V, Ilija Medan, University of Toronto