2023/03/27 by Thomas Bakx, Toshiki Kurita, Bakx, Thomas +7 · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.2303.15565
openalex publication_date 2023/03/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We test the regime of validity of the effective field theory (EFT) of intrinsic alignments (IA) at the one-loop level by comparing with 3D halo shape statistics in N-body simulations. This model is based on the effective field theory of large-scale structure (EFT of LSS) and thus a theoretically well-motivated extension of the familiar non-linear alignment (NLA) model and the tidal-alignment-tidal-torquing (TATT) model. It contains a total of 8 free bias parameters. Specifically, we measure the dark matter halo shape-shape multipoles PEE(0)(k), PEE(2)(k), PBB(0)(k), PBB(2)(k) as well as the matter-shape multipoles PδE(0)(k), PδE(2)(k) from the simulations and perform a joint fit to determine the largest wavenumber kmax up to which the theory predictions from the EFT of IA are consistent with the measurements. We find that the EFT of IA is able to describe intrinsic alignments of dark matter halos up to kmax=0.30 h/Mpc at z=0. This demonstrates a clear improvement over other existing alignment models like NLA and TATT, which are only accurate up to kmax=0.05 h/Mpc . We examine the posterior distributions of the higher-order bias parameters, and show that their inclusion is necessary to describe intrinsic alignments in the quasi-linear regime. Further, the EFT of IA is able to accurately describe the auto-spectrum of intrinsic alignment B-modes, in contrast to the other alignment models considered.