Nonlinear Reconstruction of the Velocity Field

Abstract

We propose a new velocity reconstruction method based on the displacement estimation of recently developed methods. The velocity is first reconstructed by transfer functions in Lagrangian space and then mapped into Eulerian space. High-resolution simulations are used to test the performance. We find that the new reconstruction method outperforms the standard velocity reconstruction in the sense of better cross-correlation coefficient, less velocity misalignment, and smaller amplitude difference. We conclude that this new method has the potential to improve large-scale structure sciences involving velocity reconstruction, such as kinetic Sunyaev–Zel’dovich measurement and supernova cosmology.