Sloan Digital Sky Survey IV

Sloan Digital Sky Survey IV
Name	Sloan Digital Sky Survey IV
Founded	2014
Location	Apache Point Observatory; Las Campanas Observatory

Contents

Sloan Digital Sky Survey IV

The fourth phase of a multi-decade astronomical program, SDSS‑IV continued wide-field optical and infrared surveys to map the Milky Way, galaxy evolution, and large-scale structure. SDSS‑IV connected previous initiatives led by the Apache Point Observatory, the Johns Hopkins University, the Max Planck Institute for Astronomy, and the University of California, Berkeley to modern instrumentation and international partners including institutions in Chile, Germany, and the United Kingdom. The program combined spectroscopic, integral-field, and infrared techniques to serve communities working on topics ranging from stellar populations to cosmology, producing public data releases that supported researchers at the Harvard–Smithsonian Center for Astrophysics, Princeton University, and numerous observatories.

Background and Objectives

SDSS‑IV built on the legacy of prior phases associated with the Sloan Foundation, the Alfred P. Sloan Foundation, and the original SDSS project collaborations at Fermilab, Brookhaven National Laboratory, and the Lawrence Berkeley National Laboratory. Its primary objectives aligned with mapping the Milky Way stellar structure, probing galaxy assembly history tied to Hubble Space Telescope imaging programs, and constraining dark energy through large redshift surveys used by researchers at Carnegie Mellon University, University of Oxford, and the Max Planck Society. Leadership included scientists affiliated with the University of Washington, the University of Tokyo, and the Instituto de Astrofísica de Canarias who coordinated targets overlapping legacy surveys such as the Two Micron All Sky Survey and the Galaxy Evolution Explorer.

SDSS‑IV employed upgraded spectrographs and fiber systems developed with teams at University of Wisconsin–Madison, Pennsylvania State University, and the Harvard & Smithsonian Center for Astrophysics. Key hardware included an infrared spectrograph derived from work at the University of Virginia and an integral-field unit produced with expertise from the University of Oxford and the Max Planck Institute for Extraterrestrial Physics. Observations were carried out from the Apache Point Observatory in New Mexico and complemented by southern hemisphere operations at Las Campanas Observatory in Chile, enabling coordination with programs at the European Southern Observatory and the National Optical Astronomy Observatory.

APOGEE-2 expanded the high-resolution infrared stellar spectroscopy efforts pioneered by teams at the University of Virginia, the University of Florida, and the Carnegie Institution for Science to include southern targets selected with assistance from the Pontificia Universidad Católica de Chile and the Observatorio Astronómico Nacional. MaNGA leveraged integral-field spectroscopy developed in collaboration with scientists at New York University, the University of Chicago, and the University of Cambridge to map internal kinematics and stellar populations in galaxies overlapping catalogs from the Sloan Digital Sky Survey imaging and the Pan-STARRS survey. eBOSS continued cosmological redshift measurements building on methods refined by the Baryon Oscillation Spectroscopic Survey and teams at Princeton University, Yale University, and the University of Portsmouth to measure baryon acoustic oscillations and grow samples used by researchers from the Kavli Institute for Cosmological Physics.

Data reduction pipelines were developed and maintained by software groups at the Flatiron Institute, the University of Utah, and the Astrophysics Research Institute, producing calibrated spectra, redshift catalogs, stellar parameters, and integral-field datacubes. SDSS‑IV released value-added catalogs used by scientists at the Max Planck Institute for Astronomy, the Institute for Astronomy, University of Hawaii, and the Space Telescope Science Institute for cross-matched studies with datasets from the Gaia mission, the Chandra X-ray Observatory, and the Wide-field Infrared Survey Explorer. Data products supported machine-learning efforts at the Allen Institute for AI and statistical analyses performed by teams at the Statistical Laboratory, Cambridge.

Scientific outcomes included improved maps of the Milky Way bar and disk structure used by research groups at the University of Arizona and the Observatoire de Paris, measurements of stellar abundance trends cited by the Max Planck Institute for Astronomy, and detailed studies of galaxy quenching presented by teams at Rutgers University and the University of Toronto. Cosmological constraints from eBOSS influenced models discussed at the Institute for Advanced Study and in collaborations with the Dark Energy Survey consortium and researchers at the Kavli Institute for Particle Astrophysics and Cosmology. MaNGA results informed theories developed at the California Institute of Technology and the University of California, Santa Cruz about feedback from active galactic nuclei studied in tandem with observations from the Very Large Array and the Atacama Large Millimeter/submillimeter Array.

The SDSS‑IV collaboration comprised universities and institutions such as University of California, Berkeley, University of Colorado Boulder, Stony Brook University, Australian National University, and international partners including the National Astronomical Observatory of Japan and the Instituto de Astrofísica de Canarias. Operations coordination involved site teams at the Apache Point Observatory and the Las Campanas Observatory, scheduling overseen by project offices linked to the Sloan Foundation and technical support from the National Science Foundation. The program ran from 2014 into the late 2010s, overlapping successor initiatives with involvement from organizations like the Simons Foundation and feeding datasets into archives curated by the Astrophysical Research Consortium and the National Optical-Infrared Astronomy Research Laboratory.

Category:Astronomical surveys