Cosmological Constraints from the Redshift Dependence of the AlcockPaczynski Test: Galaxy Density Gradient Field
Abstract
We propose a method based on the redshift dependence of the AlcockPaczynski (AP) test to measure the expansion history of the universe. It uses the isotropy of the galaxy density gradient field to constrain cosmological parameters. If the density parameter Ω_{ m } or the dark energy equation of state w are incorrectly chosen, the gradient field appears to be anisotropic with the degree of anisotropy varying with redshift. We use this effect to constrain the cosmological parameters governing the expansion history of the universe. Although redshiftspace distortions (RSD) induced by galaxy peculiar velocities also produce anisotropies in the gradient field, these effects are close to uniform in magnitude over a large range of redshift. This makes the redshift variation of the gradient field anisotropy relatively insensitive to the RSD. By testing the method on mock surveys drawn from the Horizon Run 3 cosmological Nbody simulations, we demonstrate that the cosmological parameters can be estimated without bias. Our method is complementary to the baryon acoustic oscillation or topology methods as it depends on D_{AH} , the product of the angular diameter distance and the Hubble parameter.
 Publication:

The Astrophysical Journal
 Pub Date:
 December 2014
 DOI:
 10.1088/0004637X/796/2/137
 arXiv:
 arXiv:1412.3564
 Bibcode:
 2014ApJ...796..137L
 Keywords:

 cosmological parameters;
 dark energy;
 largescale structure of universe;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Theory
 EPrint:
 7 pages, 5 figures. Accepted by ApJ. A companion paper investigating redshift dependence of AP using twopoint correlation function method will appear soon. We are working on the application of this method to BOSS data