The RayGalGroupSims cosmological simulation suite for the study of relativistic effects: An application to lensingmatter clustering statistics
Abstract
Context. General relativistic effects on the clustering of matter in the Universe provide a sensitive probe of cosmology and gravity theories that can be tested with the upcoming generation of galaxy surveys. These will require the availability of accurate model predictions, from large linear scales to small nonlinear ones.
Aims: Here, we present a suite of largevolume highresolution Nbody simulations specifically designed to generate lightcone data for the study of relativistic effects on lensingmatter observables without the use of simplifying approximations. As a case study application of these data, we perform an analysis of the relativistic contributions to the lensingmatter power spectra and crosspower spectra.
Methods: The RayGalGroupSims suite (RAYGAL for short) consists of two Nbody simulations of (2625 h^{−1} Mpc)^{3} volume with 4096^{3} particles of a standard flat ΛCDM model and a nonstandard wCDM phantom dark energy model with a constant equation of state. Lightcone data from the simulations have been generated using a parallel raytracing algorithm that has integrated more than 1 billion geodesic equations without the use of the flatsky or Born approximation.
Results: Catalogues and maps with relativistic weak lensing that include postBorn effects, magnification bias (MB), and redshiftspace distortions (RSDs) due to gravitational redshift, Doppler, transverse Doppler, and integrated SachsWolfeReesSciama effects are publicly released. Using this dataset, we are able to reproduce the linear and quasilinear predictions from the CLASS relativistic code for the ten power spectra and crossspectra (3 × 2 points) of the matterdensity fluctuation field and the gravitational convergence at z = 0.7 and z = 1.8. We find a 130% level contribution from both MB and RSDs to the matter power spectrum, while the fingersofGod effect is visible at lower redshift in the nonlinear regime. Magnification bias also contributes at the 10−30% level to the convergence power spectrum, leading to a deviation between the shear power spectrum and the convergence power spectrum. Magnification bias also plays a significant role in the galaxygalaxy lensing by decreasing the densityconvergence spectra by 20% and coupling nontrivial configurations (such as the configuration with the convergence at the same redshift as the density, or at even lower redshifts).
Conclusions: The cosmological analysis shows that the relativistic 3 × 2 points approach is a powerful cosmological probe. Our unified approach to relativistic effects is an ideal framework for the investigation of gravitational effects in galaxy studies (e.g., clustering and weak lensing) as well as their effects in galaxy cluster, group, and void studies (e.g., gravitational redshifts and weak lensing) and cosmic microwave background studies (e.g., integrated SachsWolfeReesSciama and weak lensing).
 Publication:

Astronomy and Astrophysics
 Pub Date:
 May 2022
 DOI:
 10.1051/00046361/202141908
 arXiv:
 arXiv:2111.08745
 Bibcode:
 2022A&A...661A..90R
 Keywords:

 cosmology: theory;
 largescale structure of Universe;
 dark energy;
 dark matter;
 gravitational lensing: weak;
 methods: numerical;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology
 EPrint:
 24 pages, 19 figures, submitted to A&