Institute for Advanced Study/Princeton University Early Universe/Cosmology Lunch Discussion
First Measurement of 3-Dimensional Reconstructed Velocity Fields from the Kinetic Sunyaev-Zeldovich Effect
The cosmic velocity field is an unbiased probe of the total matter distribution but is challenging to measure directly at intermediate and high redshifts. The large-scale velocity field imprints a signal in the cosmic microwave background (CMB) through the kinetic Sunyaev-Zeldovich (kSZ) effect. We perform the first 3d reconstruction of the large-scale velocity field from the kSZ effect by applying a quadratic estimator to CMB temperature maps and the 3d positions of galaxies. We measure the galaxy-velocity cross-power spectrum, detect the presence of the kSZ signal at a signal-to-noise ratio of over seven sigmas, and derive constraints on local primordial non-Gaussianity. This pathfinder measurement sets the stage for joint galaxy-CMB kSZ constraints to significantly enhance the information obtained from galaxy surveys through sample variance cancellation.