Legacy Survey of Space and Time

Legacy Survey of Space and Time. A monumental astronomical survey conducted by the Vera C. Rubin Observatory, the LSST will image the entire visible southern sky from its site on Cerro Pachón in Chile. Over a planned ten-year period, it will create an unprecedented cinematic map of the universe, detecting tens of billions of galaxies and stars. This vast data set is designed to address fundamental questions in cosmology and astrophysics, from the nature of dark energy to the structure of our own Milky Way.

Overview

The survey represents the core mission of the Vera C. Rubin Observatory, a facility funded by the National Science Foundation and the United States Department of Energy. It builds upon the legacy of previous wide-field surveys like the Sloan Digital Sky Survey and the Dark Energy Survey, but with a vastly greater scale and depth. The operational base is the Simonyi Survey Telescope, an innovative wide-field reflector, which will enable the project to scan the sky with unparalleled speed and sensitivity. The resulting data archive, managed by the SLAC National Accelerator Laboratory, will be one of the largest non-proprietary data sets in the world, transforming the field of time-domain astronomy.

Scientific goals

The primary scientific drivers are the investigation of dark energy and dark matter, which constitute most of the universe but remain poorly understood. By precisely measuring the weak gravitational lensing of billions of galaxies and cataloging millions of supernovae, scientists aim to constrain the properties of dark energy and the evolution of cosmic structure. A major goal is to produce a detailed inventory of the Solar System, potentially discovering thousands of new objects like trans-Neptunian objects and near-Earth asteroids, including those that might pose a hazard to Earth. Furthermore, the survey will enable studies of the changing sky, detecting optical transient events like gamma-ray burst afterglows, stellar flares, and the mergers of neutron stars.

Instrumentation and design

The survey's capabilities are enabled by two key technological marvels. The Simonyi Survey Telescope features an 8.4-meter primary mirror and a unique three-mirror design, providing an exceptionally wide field of view of 9.6 square degrees. The camera is the 3.2-gigapixel LSST Camera, the largest digital camera ever constructed for astronomy, built by a team at SLAC National Accelerator Laboratory. This camera, equipped with 189 charge-coupled device sensors and a complex filter system, will take a pair of 15-second exposures every 20 seconds, generating about 20 terabytes of data each night. The data will be processed in near-real-time by sophisticated pipelines at the National Center for Supercomputing Applications and other data facilities.

Data products and access

The project will produce two main tiers of data products for the global scientific community and the public. The first is a massive, frequently updated public data release, including catalogs of detected objects, their properties, and alerts for variable and moving sources issued within 60 seconds of detection. This alert stream will be distributed via brokers like the Astronomical Event Observatory Network to enable rapid follow-up by telescopes worldwide, including the Hubble Space Telescope and the James Webb Space Telescope. The second tier consists of more advanced, deep co-added data sets and specialized catalogs released annually, which will be accessible through platforms like the Mikulski Archive for Space Telescopes and the NOIRLab data lab.

Collaboration and timeline

The effort is a massive international collaboration involving hundreds of scientists and engineers from institutions like the Association of Universities for Research in Astronomy, Lawrence Livermore National Laboratory, and international partners in Chile, the United Kingdom, and elsewhere. Major construction milestones included the completion of the telescope dome and the delivery of the primary mirror. Following the engineering first light anticipated in 2025, a multi-year commissioning period will commence before the official start of the ten-year survey. The data collected over this decade is expected to drive astronomical discovery for generations, much like the Palomar Observatory Sky Survey did in the 20th century.

Category:Astronomical surveys Category:Vera C. Rubin Observatory