The Simons Observatory: science goals and forecasts

Abstract

The Simons Observatory (SO) is a new cosmic microwave background experiment being built on Cerro Toco in Chile, due to begin observations in the early 2020s. We describe the scientific goals of the experiment, motivate the design, and forecast its performance. SO will measure the temperature and polarization anisotropy of the cosmic microwave background in six frequency bands centered at: 27, 39, 93, 145, 225 and 280 GHz. The initial configuration of SO will have three small-aperture 0.5-m telescopes and one large-aperture 6-m telescope, with a total of 60,000 cryogenic bolometers. Our key science goals are to characterize the primordial perturbations, measure the number of relativistic species and the mass of neutrinos, test for deviations from a cosmological constant, improve our understanding of galaxy evolution, and constrain the duration of reionization. The small aperture telescopes will target the largest angular scales observable from Chile, mapping ≈ 10% of the sky to a white noise level of 2 μK-arcmin in combined 93 and 145 GHz bands, to measure the primordial tensor-to-scalar ratio, r , at a target level of σ( r )=0.003. The large aperture telescope will map ≈ 40% of the sky at arcminute angular resolution to an expected white noise level of 6 μK-arcmin in combined 93 and 145 GHz bands, overlapping with the majority of the Large Synoptic Survey Telescope sky region and partially with the Dark Energy Spectroscopic Instrument. With up to an order of magnitude lower polarization noise than maps from the Planck satellite, the high-resolution sky maps will constrain cosmological parameters derived from the damping tail, gravitational lensing of the microwave background, the primordial bispectrum, and the thermal and kinematic Sunyaev-Zel'dovich effects, and will aid in delensing the large-angle polarization signal to measure the tensor-to-scalar ratio. The survey will also provide a legacy catalog of 16,000 galaxy clusters and more than 20,000 extragalactic sources.

Keywords

Affiliated Institutions

• University of California, Berkeley US
• Université Paris Cité FR
• Sensors (United States) US
• The University of Melbourne AU
• Scuola Internazionale Superiore di Studi Avanzati IT
• University of Manchester GB
• AlbaNova SE
• Kavli Institute for Particle Astrophysics and Cosmology US
• Carnegie Mellon University US
• University of Toronto CA
• University of Pennsylvania US
• Sorbonne Paris Cité FR
• Centre National de la Recherche Scientifique FR
• University of Arizona US
• Canadian Institute for Theoretical Astrophysics CA
• Pennsylvania State University US
• Institut d'Astrophysique Spatiale FR
• University of Florida US
• McGill University CA
• University of Trieste IT
• Cornell University US
• University of Sussex GB
• Institute for Advanced Study US
• Cardiff University GB
• Université Paris-Saclay FR
• Commissariat à l'Énergie Atomique et aux Énergies Alternatives FR
• Florida State University US
• Lawrence Berkeley National Laboratory US
• University of Cambridge GB
• University of New Mexico US
• Université Paris-Sud FR
• Flatiron Health (United States) US
• Pontificia Universidad Católica de Chile CL
• University of Oxford GB
• University of KwaZulu-Natal ZA
• Stockholm University SE
• Kavli Institute for the Physics and Mathematics of the Universe JP
• Simon Fraser University CA
• Istituto Nazionale di Fisica Nucleare, Sezione di Trieste IT
• Arizona State University US
• Flatiron Institute
• University of Pittsburgh US
• Stanford University US
• SLAC National Accelerator Laboratory US
• Princeton University US
• University of California, San Diego US
• University of Michigan US
• High Energy Accelerator Research Organization JP
• University of Southern California US
• The University of Tokyo JP
• Rutgers, The State University of New Jersey US
• Tohoku University JP
• Laboratoire AstroParticule et Cosmologie FR
• Stony Brook University US

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