Imprints of relativistic effects on the asymmetry of the halo crosscorrelation function: from linear to nonlinear scales
Abstract
The apparent distribution of largescale structures in the Universe is sensitive to the velocity/potential of the sources as well as the potential along the line of sight through the mapping from real space to redshift space (redshiftspace distortions, RSD). Since odd multipoles of the halo crosscorrelation function vanish when considering standard Doppler RSD, the dipole is a sensitive probe of relativistic and wideangle effects. We build a catalogue of ten million haloes (Milky Way size to galaxycluster size) from the fullsky light cone of a new `RayGalGroupSims' Nbody simulation which covers a volume of (2.625 h^{1} Gpc)^{3} with 4096^{3} particles. Using raytracing techniques, we find the null geodesics connecting all the sources to the observer. We then selfconsistently derive all the relativistic contributions (in the weakfield approximation) to RSD: Doppler, transverse Doppler, gravitational, lensing and integrated SachsWolfe. It allows us, for the first time, to disentangle all contributions to the dipole from linear to nonlinear scales. At large scale, we recover the linear predictions dominated by a contribution from the divergence of neighbouring line of sights. While the linear theory remains a reasonable approximation of the velocity contribution to the dipole at nonlinear scales it fails to reproduce the potential contribution below 3060 h^{1} Mpc (depending on the halo mass). At scales smaller than ∼10 h^{1} Mpc, the dipole is dominated by the asymmetry caused by the gravitational redshift. The transition between the two regimes is mass dependent as well. We also identify a new nontrivial contribution from the nonlinear coupling between potential and velocity terms.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 February 2019
 DOI:
 10.1093/mnras/sty3206
 arXiv:
 arXiv:1803.04294
 Bibcode:
 2019MNRAS.483.2671B
 Keywords:

 gravitational lensing: weak;
 methods: numerical;
 galaxies: distances and redshifts;
 largescale structure of Universe;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology
 EPrint:
 29 pages, accepted