Direct Determination of Expansion History Using Redshift Distortions

Abstract

We investigate the direct determination of expansion history using redshift distortions without plugging into detailed cosmological parameters. The observed spectra in redshift space include a mixture of information: fluctuations of density-density and velocity-velocity spectra, and distance measures of perpendicular and parallel components to the line of sight. Unfortunately it is hard to measure all the components simultaneously without any specific prior assumption. Common prior assumptions include a linear/quasi-linear model of redshift distortions or a model for the shape of the power spectra, which eventually breaks down on small scales at later epochs where nonlinear structure formation disturbs coherent growth. The degeneracy breaking, between the effect of cosmic distances and redshift distortions for example, depends on the prior we assume. An alternative approach is to utilize the cosmological principle inscribed in the heart of the Friedmann-Lematre-Robertson-Walker (hereafter FLRW) universe, that is, the specific relation between the angular diameter distance and the Hubble parameter, in this degeneracy breaking. We show that utilizing this FLRW prior early in the step of distinguishing the distance effect from redshift distortions helps us improve the detectability of power spectra and distance measures with no leaning on a combination of other experiments.

10 pages, 7 figures, published in Physical Review D

References in corpus (12)

• Cosmological Constraints from the SDSS Luminous Red Galaxies
• A test of the nature of cosmic acceleration using galaxy redshift distortions
• The Large Scale Structure of f(R) Gravity
• Resumming Cosmological Perturbations via the Lagrangian Picture: One-loop Results in Real Space and in Redshift Space
• Nonlinear Evolution of Baryon Acoustic Oscillations
• Testing cosmological structure formation using redshift-space distortions
• Observational Tests of Modified Gravity
• Testing LCDM with the Growth Function δ(a): Current Constraints
• Modelling redshift space distortions in hierarchical cosmologies
• Differentiating dark energy and modified gravity with galaxy redshift surveys
• Perturbation Theory Reloaded II: Non-linear Bias, Baryon Acoustic Oscillations and Millennium Simulation In Real Space
• Consistency test of general relativity from large scale structure of the Universe