TY - JOUR

T1 - Extending the modeling of the anisotropic galaxy power spectrum to k = 0.4 hMpc-1

AU - Hand, Nick

AU - Seljak, Uroš

AU - Beutler, Florian

AU - Vlah, Zvonimir

PY - 2017/10/10

Y1 - 2017/10/10

N2 - 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 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 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 hMpc−1, we find 15-30% gains in the statistical precision of f σ8 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 f σ8 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.

AB - 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 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 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 hMpc−1, we find 15-30% gains in the statistical precision of f σ8 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 f σ8 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.

UR - https://researchportal.port.ac.uk/portal/en/publications/extending-the-modeling-of-the-anisotropic-galaxy-power-spectrum-to-k--04-hmpc1(677de8bc-9fe7-46de-8cf8-f0e51b0fbb5a).html

U2 - 10.1088/1475-7516/2017/10/009

DO - 10.1088/1475-7516/2017/10/009

M3 - Article

JO - Journal of Cosmology and Astroparticle Physics (JCAP)

JF - Journal of Cosmology and Astroparticle Physics (JCAP)

SN - 1475-7516

ER -