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Title: Galaxy power spectrum in redshift space: Combining perturbation theory with the halo model

Theoretical modeling of the redshift-space power spectrum of galaxies is crucially important to correctly extract cosmological information from galaxy redshift surveys. The task is complicated by the nonlinear biasing and redshift space distortion (RSD) effects, which change with halo mass, and by the wide distribution of halo masses and their occupations by galaxies. One of the main modeling challenges is the existence of satellite galaxies that have both radial distribution inside the halos and large virial velocities inside halos, a phenomenon known as the Finger-of-God (FoG) effect. We present a model for the redshift-space power spectrum of galaxies in which we decompose a given galaxy sample into central and satellite galaxies and relate different contributions to the power spectrum to 1-halo and 2-halo terms in a halo model. Our primary goal is to ensure that any parameters that we introduce have physically meaningful values, and are not just fitting parameters. For the lowest order 2-halo terms we use the previously developed RSD modeling of halos in the context of distribution function and perturbation theory approach. This term needs to be multiplied by the effect of radial distances and velocities of satellites inside the halo. To this one needs to addmore » the 1-halo terms, which are nonperturbative. We show that the real space 1-halo terms can be modeled as almost constant, with the finite extent of the satellites inside the halo inducing a small k2R2 term over the range of scales of interest, where R is related to the size of the halo given by its halo mass. Furthermore, we adopt a similar model for FoG in redshift space, ensuring that FoG velocity dispersion is related to the halo mass. For FoG k2 type expansions do not work over the range of scales of interest and FoG resummation must be used instead. We test several simple damping functions to model the velocity dispersion FoG effect. Applying the formalism to mock galaxies modeled after the “CMASS” sample of the BOSS survey, we find that our predictions for the redshift-space power spectra are accurate up to k ≃ 0.4 h Mpc–1 within 1% if the halo power spectrum is measured using N-body simulations and within 3% if it is modeled using perturbation theory.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. The Univ. of Tokyo, Chiba (Japan)
  2. Univ. of California, CA (United States)
  3. Univ. of California, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  4. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  5. Univ. de Geneve, Geneve (Switzerland)
Publication Date:
OSTI Identifier:
1263410
Report Number(s):
SLAC-PUB--16628
Journal ID: ISSN 1550-7998; PRVDAQ; arXiv:1506.05814
Grant/Contract Number:
AC02-76SF00515
Type:
Accepted Manuscript
Journal Name:
Physical Review. D, Particles, Fields, Gravitation and Cosmology
Additional Journal Information:
Journal Volume: 92; Journal Issue: 10; Journal ID: ISSN 1550-7998
Publisher:
American Physical Society (APS)
Research Org:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS astrophysics; ASTRO