2015/03/31 by Simon Foreman, Leonardo Senatore · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Cosmic microwave background #Dark matter #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gravitational lens #Matter power spectrum #Redshift #Scale (ratio) #Scientific Research and Discoveries #Spectral density #Weak gravitational lensing #astro-ph.CO #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1088/1475-7516/2016/04/033
40 pages, 20 figures. v2: JCAP published version, improved theory-error estimates, extended explanations and minor corrections
arxiv created 2016/04/07 · openalex publication_date 2016/04/18 · arxiv updated 2016/04/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study the prediction of the Effective Field Theory of Large Scale Structures (EFTofLSS) for the matter power spectrum at different redshifts. In previous work, we found that the two-loop prediction can match the nonlinear power spectrum measured from N -body simulations at redshift zero within approximately 2% up to k ∼ 0.6 h Mpc -1 after fixing a single free parameter, the so-called "speed of sound". We determine the time evolution of this parameter by matching the EFTofLSS prediction to simulation output at different redshifts, and find that it is well-described by a fitting function that only includes one additional parameter. After the two free parameters are fixed, the prediction agrees with nonlinear data within approximately 2% up to at least k ∼ 1 h Mpc -1 at z ⩾ 1, and also within approximately 5% up to k ∼ 1.2 h Mpc -1 at z =1 and k ∼ 2.3 h Mpc -1 at z =3, a major improvement with respect to other perturbative techniques. We also develop an accurate way to estimate where the EFTofLSS predictions at different loop orders should fail, based on the sizes of the next-order terms that are neglected, and find agreement with the actual comparisons to data. Finally, we use our matter power spectrum results to perform analytical calculations of lensing potential power spectra corresponding to both CMB and galaxy lensing. This opens the door to future direct applications of the EFTofLSS to observations of gravitational clustering on cosmic scales.