The SantiagoHarvardEdinburghDurham void comparison  I. SHEDding light on chameleon gravity tests
Abstract
We present a systematic comparison of several existing and new voidfinding algorithms, focusing on their potential power to test a particular class of modified gravity models  chameleon f(R) gravity. These models deviate from standard general relativity (GR) more strongly in lowdensity regions and thus voids are a promising venue to test them. We use halo occupation distribution (HOD) prescriptions to populate haloes with galaxies, and tune the HOD parameters such that the galaxy twopoint correlation functions are the same in both f(R) and GR models. We identify both threedimensional (3D) voids and twodimensional (2D) underdensities in the plane of the sky to find the same void abundance and void galaxy number density profiles across all models, which suggests that they do not contain much information beyond galaxy clustering. However, the underlying void dark matter density profiles are significantly different, with f(R) voids being more underdense than GR ones, which leads to f(R) voids having a larger tangential shear signal than their GR analogues. We investigate the potential of each void finder to test f(R) models with nearfuture lensing surveys such as EUCLID and LSST. The 2D voids have the largest power to probe f(R) gravity, with an LSST analysis of tunnel (which is a new type of 2D underdensity introduced here) lensing distinguishing at 80 and 11σ (statistical error) f(R) models with parameters, f_{R0} = 10^{5} and 10^{6}, from GR.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 May 2018
 DOI:
 10.1093/mnras/sty463
 arXiv:
 arXiv:1710.01730
 Bibcode:
 2018MNRAS.476.3195C
 Keywords:

 gravitational lensing: weak;
 dark energy;
 largescale structure of Universe;
 cosmology: theory;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 22 pages, 13 figures, version accepted for publication in MNRAS