Cosmology with the Large Synoptic Survey Telescope: an overview

The Large Synoptic Survey Telescope (LSST) is a high etendue imaging facility that is being constructed atop Cerro Pachon in northern Chile. It is scheduled to begin science operations in 2022. With an 8.4m (6.5m effective) aperture, a novel three-mirror design achieving a seeing-limited 9.6 deg(2) field of view, and a 3.2 gigapixel camera, the LSST has the deep-wide-fast imaging capability necessary to carry out an 18 000 deg(2) survey in six passbands (ugrizy) to a coadded depth of r similar to 27.5 over 10 years using 90% of its observational time. The remaining 10% of the time will be devoted to considerably deeper and faster time-domain observations and smaller surveys. In total, each patch of the sky in the main survey will receive 800 visits allocated across the six passbands with 30 s exposure visits. The huge volume of high-quality LSST data will provide a wide range of science opportunities and, in particular, open a new era of precision cosmology with unprecedented statistical power and tight control of systematic errors. In this review, we give a brief account of the LSST cosmology program with an emphasis on dark energy investigations. The LSST will address dark energy physics and cosmology in general by exploiting diverse precision probes including large-scale structure, weak lensing, type Ia supernovae, galaxy clusters, and strong lensing. Combined with the cosmic microwave background data, these probes form interlocking tests on the cosmological model and the nature of dark energy in the presence of various systematics. The LSST data products will be made available to the US and Chilean scientific communities and to international partners with no proprietary period. Close collaborations with contemporaneous imaging and spectroscopy surveys observing at a variety of wavelengths, resolutions, depths, and timescales will be a vital part of the LSST science program, which will not only enhance specific studies but, more importantly, also allow a more complete understanding of the Universe through different windows.