Redshift space power spectrum beyond Einstein-de Sitter kernels

Abstract

We develop a framework to compute the redshift space power spectrum (PS), with kernels beyond Einstein-de Sitter (EdS), that can be applied to a wide variety of generalized cosmologies. We build upon a formalism that was recently employed for standard cosmology in Chen, Vlah & White (2020), and utilize an expansion of the density-weighted velocity moment generating function that explicitly separates the magnitude of the k-modes and their angle to the line-of-sight direction dependencies. We compute the PS for matter and biased tracers to 1-loop Perturbation Theory (PT) and show that the expansion has a correct infrared and ultraviolet behavior, free of unwanted divergences. We also add Effective Field Theory (EFT) counterterms, necessary to account for small-scale contributions to PT, and employ an IR-resummation prescription to properly model the smearing of the BAO due to large scale bulk flows within Standard-PT. To demonstrate the applicability of our formalism, we apply it on the ΛCDM and the Hu-Sawicki f(R) models, and compare our numerical results against the elephant suite of N-body simulations, finding very good agreement up to k = 0.27 Mpc-1 h at z = 0.5 for the first three non-vanishing Legendre multipoles of the PS. To our knowledge, the model presented in this work is the most accurate theoretical EFT-PT for modified gravity to date, being the only one that accounts for beyond linear local biasing in redshift-space. Hence, we argue our RSD modeling is a promising tool to construct theoretical templates in order to test deviations from ΛCDM using real data obtained from the next stage of cosmological surveys such as DESI and LSST.

Cosmological Vlasov-Poisson equations for dark matter: Recent developments and connections to selected plasma problems

“…1) [114,115,116,117,118,119,120]. -Modelling the baryonic acoustic oscillation feature imprinted in statistics of cosmic structures [121,122,123,124,125,126,127]; and improving statistical predictions of the large-scale structure by pairing/emulating techniques with numerical simulations [128,129,130,131,132,133,134].…”

Testing Screened Modified Gravity

“…Using these governing equations one can solve perturbatively the Vlasov-Poisson system of equations, which consists in first approximation (no vorticity and single-stream regime) of the continuity, Euler and Poisson equations, in powers of the linear growth factor. The results of these computations at 1-loop order and beyond can be seen in references [235][236][237][238][239][240].…”

Clustering in Massive Neutrino Cosmologies via Eulerian Perturbation Theory

“…) is much more cumbersome and its expression is not very illuminating; while it can be found in eq. (C.22) of [24]. However, it simplifies considerably when it is symmetrized over its three arguments and evaluated at the wave-vectors k 1 = k, k 3 = −k 2 = p, which correspond to the configuration appearing in the one-loop computations.…”

“…More precisely, the velocity and density kernels are obtained by mapping the LPT kernels of [23] to the Eulerian framework. Furthermore, the mapping method heavily relies on a previous study [24], where the redshift-space power spectrum with generalized kernels, beyond Einstein-de Sitter (EdS), was obtained for representative modified gravity models. The latter work is, in turn, a generalization of the velocity moments expansion approach, in the form presented in [25].…”

“…We also add EFT counterterms to model the small-scales physics, which are out of reach from the PT, together with the damping of the density and velocity fields along the line-of-sight due to Redshift Space Distortions (RSD). Finally, we use the biasing scheme of [29], slightly modified in [24], to account for additional scales. In summary and to our knowledge, this is the first work that contains all the above ingredients in redshift-space for massive neutrino cosmologies.…”