Probing the Early Universe with the Simons Observatory (Benjamin Beringue, APC)
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amphi Charpak
The Simons Observatory (SO) is a new cosmic microwave background (CMB) experiment located on Cerro Toco in Chile, which began observations in early 2024. SO is designed to measure temperature and polarization anisotropies of the CMB across six frequency bands spanning 27–280 GHz. Its initial configuration comprises three 0.5-m small-aperture telescopes (SATs) and one 6-m large-aperture telescope (LAT), hosting a total of approximately 60,000 cryogenic bolometric detectors. The total detector count on both the SATs and the LAT is planned to double by 2028. The key science goals of SO include characterizing primordial perturbations, constraining the effective number of relativistic species and the sum of neutrino masses, testing deviations from a cosmological constant, improving our understanding of galaxy evolution, and placing constraints on the timing and duration of cosmic reionization. In this talk, I will present the first measurements obtained during SO’s ongoing Initial Science Observation phase. I will also discuss current developments in data-analysis pipelines led by the SciPol group at APC, as well as ongoing proposals for future extensions of the Simons Observatory.