We show that the spatial correlation of the intrinsic alignments (IAs) of galaxies, measured in galaxy redshift surveys, offers a precision route to improve the geometrical and dynamical constraints on cosmology. The IA has been treated as a contaminant against cosmological probes such as weak gravitational lensing experiments. However, the large-scale correlation of IAs is expected to follow the coherent large-scale matter inhomogeneities. Here, making use of its anisotropic nature, we show that the large-scale IA correlations help to improve the measurements of the geometric distances and growth of structure. In combination with the conventional galaxy clustering statistics, we find that constraints on equation-of-state parameter for dark energy and Hubble parameter can be tighter than those from the clustering statistics alone by a factor of more than 1.5.
@article{arxiv.2001.05962,
title = {Improving geometric and dynamical constraints on cosmology with intrinsic alignments of galaxies},
author = {Atsushi Taruya and Teppei Okumura},
journal= {arXiv preprint arXiv:2001.05962},
year = {2020}
}
Comments
6 pages, 4 figures, updated to match version published in ApJL