We investigate the properties of the 2-point galaxy correlation function at very large scales, including all geometric and local relativistic effects -- wide-angle effects, redshift space distortions, Doppler terms and Sachs-Wolfe type terms in the gravitational potentials. The general three-dimensional correlation function has a nonzero dipole and octupole, in addition to the even multipoles of the flat-sky limit. We study how corrections due to primordial non-Gaussianity and General Relativity affect the multipolar expansion, and we show that they are of similar magnitude (when f_NL is small), so that a relativistic approach is needed. Furthermore, we look at how large-scale corrections depend on the model for the growth rate in the context of modified gravity, and we discuss how a modified growth can affect the non-Gaussian signal in the multipoles.
@article{arxiv.1306.6646,
title = {Large-scale 3D galaxy correlation function and non-Gaussianity},
author = {Alvise Raccanelli and Daniele Bertacca and Olivier Dore and Roy Maartens},
journal= {arXiv preprint arXiv:1306.6646},
year = {2014}
}
Comments
13 pages, 11 figures. Matches version published on JCAP