Extending the modeling of the anisotropic galaxy power spectrum to k = 0.4 hMpc~(-1)

摘要

We present a model for the redshift-space power spectrum of galaxies and demon-strate its accuracy in describing the monopole, quadrupole, and hexadecapole of the galaxy density ?eld down to scales of k = 0.4 hMpc~(-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 ?nal 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-?delity N-body simulations, as well as realistic mock catalogs designed to simulate the BOSS DR12 CMASS data set. The suite of simu-lations 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 fσ8 is found to be small. When including scales to k = 0.4 hMpc~(-1) , we ?nd 15-30% gains in the statistical precision of fσ8 relative to k = 0.2 hMpc~(-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 fσ8 that is ~ 10-20% larger than other similar Fourier-space RSD models in the literature that use k ≤ 0.2 hMpc~(-1) , suggesting that these models likely have a too-limited parametrization.