Inflation Physics from Cosmic Velocities with Joint Galaxy and CMB Simulations
Abstract
The main objective of this project is to enable the tightest constraints on multi-field inflation to date by using cross-correlations of the cosmic microwave background (CMB) and galaxy surveys. This requires measuring cosmic velocities with the kinetic Sunyaev-Zeldovich (kSZ) effect, an imprint in the CMB that can be extracted jointly with galaxy surveys. This recently proposed application holds great promise because analysis of upcoming galaxy and CMB data is forecast to reach an uncertainty in the amplitude of primordial local non-Gaussianity, fNL, below sigma(fNL)~1, bringing observations to the regime where models of inflation involving an additional spectator field can be discriminated. Currently, theoretical predictions are inadequate for application to upcoming observations, due to an insufficient understanding of the systematic effects inherent to this new probe of the early universe. Detailed verification with a set of numerical simulations that models primordial non-Gaussianity as well as relevant survey systematics -- with correlated large-scale structure for CMB and galaxy observables -- will be crucial for putting inflation physics from kSZ on a robust footing. We propose to develop a novel approach for jointly simulating large-scale structure and the correlated CMB, resulting in the only available simulated dataset of the kind required to measure the kSZ effect through cross-correlations of large-scale structure observatories like SPHEREx, Euclid, Rubin and Roman with CMB surveys like Simons Observatory and CMB-S4. In addition, the simulations will be publicly available to the community and allow pan-experiment collaboration for joint cosmological analyses with a wide array of observables. The novel techniques developed will enable simulations to be produced efficiently, paving the way for combining multiple observational probes through likelihood-free or simulation-based inference. Our joint sky simulation framework will satisfy a key theoretical requirement for making discoveries in fundamental physics from cosmic velocity measurements using galaxies and the CMB.
- Publication:
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NASA ATP Proposal
- Pub Date:
- 2021
- Bibcode:
- 2021atp..prop..145M