The BEHOMO project: ? Lemaitre-Tolman-Bondi N-body simulations⋆

Context. Our universe may feature large-scale inhomogeneities and anisotropies that cannot be explained by the standard model of cosmology, that is, the homogeneous and isotropic Friedmann-Lemaitre-Robertson-Walker metric, on which the ? cold dark matter model is built, may not accurately describe observations. Currently, there is not a satisfactory understanding of the evolution of the large-scale structure on an inhomogeneous background. Aims. We have launched the cosmology beyond homogeneity and isotropy (BEHOMO) project to study the inhomogeneous ? Lemaitre-Tolman-Bondi model with the methods of numerical cosmology. Understanding the evolution of the large-scale structure is a necessary step in constraining inhomogeneous models with present and future observables and placing the standard model on more solid ground. Methods. We perform Newtonian N-body simulations, whose accuracy in describing the background evolution is checked against the general relativistic solution. The large-scale structure of the corresponding ? cold dark matter simulation is also validated. Results. We obtain the first set of simulations of the ? Lemaitre-Tolman-Bondi model ever produced. The data products consist of 11 snapshots between redshift 0 and 3.7 for each of the 68 simulations that have been performed, together with halo catalogs and lens planes relative to 21 snapshots, between redshift 0 and 4.2, for a total of approximately 180 TB of data. Conclusions. We plan to study the growth of perturbations at the linear and nonlinear level, gravitational lensing, and cluster abundances and proprieties.

Automated summary

The study focuses on the evolution of large-scale structures in an inhomogeneous background using numerical cosmology. By conducting simulations, the researchers aim to gain a better understanding of the cosmic evolution and refine the standard model.