Imprints of relativistic effects on the asymmetry of the halo cross-correlation function: from linear to non-linear scales

The apparent distribution of large-scale 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 (redshift-space distortions, RSD). Since odd multipoles of the halo cross-c...

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Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society 2019-02, Vol.483 (2), p.2671-2696
Main Authors: Breton, Michel-Andrès, Rasera, Yann, Taruya, Atsushi, Lacombe, Osmin, Saga, Shohei
Format: Article
Language:English
Subjects:
Astrophysics
General Relativity and Quantum Cosmology
Physics
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Summary:The apparent distribution of large-scale 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 (redshift-space distortions, RSD). Since odd multipoles of the halo cross-correlation function vanish when considering standard Doppler RSD, the dipole is a sensitive probe of relativistic and wide-angle effects. We build a catalogue of ten million haloes (Milky Way size to galaxy-cluster size) from the full-sky light cone of a new ‘RayGalGroupSims’ N-body simulation which covers a volume of (2.625 h^−1 Gpc)^3 with 4096^3 particles. Using ray-tracing techniques, we find the null geodesics connecting all the sources to the observer. We then self-consistently derive all the relativistic contributions (in the weak-field approximation) to RSD: Doppler, transverse Doppler, gravitational, lensing and integrated Sachs–Wolfe. It allows us, for the first time, to disentangle all contributions to the dipole from linear to non-linear 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 non-linear scales it fails to reproduce the potential contribution below 30–60 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 non-trivial contribution from the non-linear coupling between potential and velocity terms.
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/sty3206