Details

Autor(en) / Beteiligte

• Philcox, Oliver H. E.
• Spergel, David N.
• Villaescusa-Navarro, Francisco

Titel

Effective halo model: Creating a physical and accurate model of the matter power spectrum and cluster counts

Ist Teil von

• Physical review. D, 2020-06, Vol.101 (12), p.1, Article 123520

Ort / Verlag

College Park: American Physical Society

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We introduce a physically motivated model of the matter power spectrum, based on the halo model and perturbation theory. This model achieves 1% accuracy on all k -scales between k = 0.02 h Mpc−1 to k = 1 h Mpc−1. Our key ansatz is that the number density of halos depends on the nonlinear density contrast filtered on some unknown scale R . Using the effective field theory of large scale structure to evaluate the two-halo term, we obtain a model for the power spectrum with only two fitting parameters: R and the effective "sound speed," which encapsulates small-scale physics. This is tested with two suites of cosmological simulations across a broad range of cosmologies and found to be highly accurate. Due to its physical motivation, the statistics can be easily extended beyond the power spectrum; we additionally derive the one-loop covariance matrices of cluster counts and their combination with the matter power spectrum. This yields a significantly better fit to simulations than previous models, and includes a new model for supersample effects, which is rigorously tested with separate universe simulations. At low redshift, we find a significant ( ∼ 10 % ) exclusion covariance from accounting for the finite size of halos which has not previously been modeled. Such power spectrum and covariance models will enable joint analysis of upcoming large-scale structure surveys, gravitational lensing surveys, and cosmic microwave background maps on scales down to the nonlinear scale. We provide a publicly released python code.