Mid-scale RI-2: Advanced Millimeter Survey Instrumentation in Chile

Large scale millimeter-wave surveys of the sky at high resolution, designed to explore the origin and evolution of the universe, can address a wide range of pressing science questions. The next generation of Cosmic Microwave Background (CMB) instruments will reveal much about the origin and evolution of the Universe, about the fundamental physics driving its birth and growth, and about its dynamic contents as they interact and change.

Achieving these goals requires a significant improvement both in instrumental capabilities and in data pipelines. Building on significant investment by the Simons Foundation (SF) in the Simons Observatory (SO), this award provides three Advanced SO (ASO) deliverables, which will increase the scientific reach, increase access to the wider community not expert in the instrumentation, and decrease the environmental impact of the facility and improve relations with the host country of Chile.

There are extensive plans for public outreach and the training of early career researchers during the survey activity once ASO is operational. Meanwhile, implementation of the infrastructure involves more than a dozen graduate students and around ten postdocs, as key players. There will be opportunities for young physicists to work with SO scientists on summer activities, and extensive training on the ASO infrastructure, mentored by SO scientists in a collaboration with the Simons Foundation and the National Society of Black Physicists.

The contributions from this award are: (i) 30,000 new detectors and associated optics for the SO six-meter diameter Large Aperture Telescope, doubling its mapping speed and enabling the detection of transient objects; (ii) an end-to-end data pipeline to produce and validate maps of all SO data, and generate daily light-curves of variable sources concurrent with other surveys such as those from the Rubin Observatory, and (iii) a photovoltaic power system that directly increases system sensitivity while reducing operating costs and environmental impact. This infrastructure is crucial to the survey goal, to produce millimeter-wave maps of the sky on a regular cadence.

Such maps are a critical part of the search for primordial gravitational waves, but also help understanding of galaxy evolution and the role of magnetic fields. Analysis will: (1) reveal physical conditions in the early universe and constrain any new light particles; (2) measure the distribution of mass, electron pressure, and electron momentum in the more recent universe, and combine with large-scale structure surveys to determine the neutrino mass and the effects of dark energy; (3) measure the distribution of electron density and pressure around galaxy groups and clusters; (4) use the thermal Sunyaev-Zel’dovich effect to find more than 30,000 galaxy clusters and more than 100,000 extragalactic millimeter sources; (5) measure the alignment of dust by magnetic fields in our Galaxy; and (6) reveal new features of the transient universe concurrent with optical observations.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.