Extending the modeling of the anisotropic galaxy power spectrum to k = 0.4 hMpc−1. Issue 10 (10th October 2017)

• Record Type: Journal Article
• Authors: Hand, Nick; Seljak, Uroš; Beutler, Florian; Vlah, Zvonimir
• Is Part Of: Journal of cosmology and astroparticle physics. Volume 2017:Issue 10(2017)
• Page Start: 009
• Page End: 009
• Publication Date: 2017-10-10
• Subjects: cosmological parameters from LSS -- power spectrum -- redshift surveys; Cosmology -- Periodicals; Astrophysics -- Periodicals; 523.0105
• DOI: 10.1088/1475-7516/2017/10/009
• Languages: English
• ISSNs: 1475-7516

Abstract

Abstract: We present a model for the redshift-space power spectrum of galaxies and demonstrate its accuracy in describing the monopole, quadrupole, and hexadecapole of the galaxy density field down to scales of k = 0.4 h Mpc −1 . The model describes the clustering of galaxies in the context of a halo model and the clustering of the underlying halos in redshift space using a combination of Eulerian perturbation theory and N -body simulations. The modeling of redshift-space distortions is done using the so-called distribution function approach. The final model has 13 free parameters, and each parameter is physically motivated rather than a nuisance parameter, which allows the use of well-motivated priors. We account for the Finger-of-God effect from centrals and both isolated and non-isolated satellites rather than using a single velocity dispersion to describe the combined effect. We test and validate the accuracy of the model on several sets of high-fidelity N -body simulations, as well as realistic mock catalogs designed to simulate the BOSS DR12 CMASS data set. The suite of simulations covers a range of cosmologies and galaxy bias models, providing a rigorous test of the level of theoretical systematics present in the model. The level of bias in the recovered values of f σ8 is found to be small. When including scales to k = 0.4 h Mpc −1, we find 15-30% gains in the statistical precision of f σ8 relative to k = 0.2 h Mpc −1 and a roughly 10–15% improvement for the perpendicular Alcock-Paczynski parameter α⊥ . Using the BOSS DR12 CMASS mocks as a benchmark for comparison, we estimate an uncertainty on f σ8 that is ∼ 10–20% larger than other similar Fourier-space RSD models in the literature that use k ⩽ 0.2 h Mpc −1, suggesting that these models likely have a too-limited parametrization.