Simons Observatory

Simons Observatory. A next-generation cosmic microwave background experiment designed to make transformative discoveries in cosmology and fundamental physics. Located in the high-altitude Atacama Desert of Chile, it is a collaborative project funded primarily by the Simons Foundation and involving leading research institutions. The observatory aims to map the afterglow of the Big Bang with unprecedented sensitivity, probing the origins of the universe and the nature of dark matter and dark energy.

Overview

The project represents a major advancement in the field of observational cosmology, building upon the legacy of experiments like the Planck (spacecraft) and the Atacama Cosmology Telescope. It is strategically situated near the existing Llano de Chajnantor Observatory to leverage the exceptionally dry, stable atmospheric conditions crucial for observing faint microwave signals. By deploying a suite of advanced telescopes and over 60,000 superconducting detectors, it will generate orders of magnitude more data than its predecessors. This vast dataset is expected to provide critical tests for theories of cosmic inflation and to precisely measure the number of neutrino species and their total mass.

Scientific goals

A primary objective is to search for primordial gravitational waves by measuring the polarization pattern of the cosmic microwave background, specifically the elusive B-mode signal, which would be a landmark discovery for physics. The observatory will also create detailed maps of the distribution of matter across cosmic history, tracing the influence of dark energy on the large-scale structure of the universe. Furthermore, it will conduct a deep survey for galaxy clusters via the Sunyaev–Zel'dovich effect, providing insights into astroparticle physics. Additional goals include studying the properties of our own Milky Way galaxy and transient phenomena in the time-domain.

Instrumentation

The facility will operate a combination of telescopes: a single large aperture telescope for surveying a wide area of sky and three smaller telescopes for deeper, high-resolution observations on a smaller patch. These instruments are equipped with state-of-the-art cryogenic receivers that house arrays of transition-edge sensor bolometers, technology advanced by institutions like the National Institute of Standards and Technology. The focal planes utilize both dichroic pixels sensitive to multiple frequency bands and sinuous antenna coupled detectors to meticulously separate the cosmic microwave background from foreground emission from sources like cosmic dust and synchrotron radiation. This multi-frequency approach is essential for component separation and achieving the required sensitivity.

Collaboration and site

The project is a collaboration led by the Simons Foundation and includes core institutions such as the University of California, San Diego, University of California, Berkeley, Princeton University, the University of Pennsylvania, and the Lawrence Berkeley National Laboratory, with contributions from many other international partners. The site is located on Cerro Toco in the Atacama Desert, adjacent to the facilities of the Atacama Cosmology Telescope and near the ALMA observatory, at an elevation of 5,200 meters. This extreme location, managed in cooperation with the Agencia Nacional de Investigación y Desarrollo of Chile, offers one of the best terrestrial environments for submillimeter astronomy due to its minimal atmospheric water vapor.

Expected timeline and results

Construction and deployment of the telescopes and receivers began in the late 2010s, with full operations anticipated to commence in the mid-2020s. The first major data release is expected to occur within a few years of beginning observations, potentially rivaling or exceeding the cosmological impact of data from the European Space Agency's Euclid (spacecraft) mission. The results are predicted to constrain key cosmological parameters, such as the tensor-to-scalar ratio, to unprecedented precision, offering a definitive test for many models of inflation (cosmology). The legacy data products will also serve as a rich resource for the broader astronomical community, enabling studies far beyond the primary science goals.

Category:Astronomical observatories in Chile Category:Cosmic microwave background experiments Category:Simons Foundation