Cosmological hydrodynamics with adaptive mesh refinement

Abstract

Abstract.A new N-body and hydrodynamical code, called RAMSES, is presented. It has been designed to study structure formation in the universe with high spatial resolution. The code is based on Adaptive Mesh Refinement (AMR) technique, with a tree-based data structure allowing recursive grid refinements on a cell-by-cell basis. The N-body solver is very similar to the one developed for the ART code (Kravtsov et al. 1997), with minor differences in the exact implementation. The hydrodynamical solver is based on a second-order Godunov method, a modern shock-capturing scheme known to compute accurately the thermal history of the fluid component. The accuracy of the code is carefully estimated using various test cases, from pure gas dynamical tests to cosmological ones. The specific refinement strategy used in cosmological simulations is described, and potential spurious effects associated with shock waves propagation in the resulting AMR grid are discussed and found to be negligible. Results obtained in a large N-body and hydrodynamical simulation of structure formation in a low density ΛCDM universe are reported, with 256 3 particles and 4.1 × 10 7 cells in the AMR grid, reaching a formal resolution of 8192 3 . A convergence analysis of different quantities, such as dark matter density power spectrum, gas pressure power spectrum and individual haloe temperature profiles, shows that numerical results are converging down to the actual resolution limit of the code, and are well reproduced by recent analytical predictions in the framework of the halo model.

The rise and fall of stellar across the peak of cosmic star formation history: effects of mergers versus diffuse stellar mass acquisition

“…The size of the simulation box is L box = 100 h −1 Mpc on a side, and the volume contains 1024 3 dark matter (DM) particles, corresponding to a DM mass resolution of MDM,res = 8 × 10 7 M⊙. The simulation is run with the ramses code (Teyssier 2002), and the initially coarse 1024 3 grid is adaptively refined down to ∆x = 1 proper kpc, with refinement triggered in a quasi-Lagrangian manner: if the number of DM particles becomes greater than 8, or the total baryonic mass reaches 8 times the initial DM mass resolution in a cell. It lead to a typical number of 6.5 × 10 9 gas resolution elements (leaf cells) in the Horizon-AGN simulation at z = 1.…”

Dusty star-forming galaxies at high redshift

“…A number of publicly available codes exist for the purposes of cosmological simulations that are commonly employed 25 , such as amiga, gadget, enzo, flash, and ramses (Knebe et al, 2001;Springel, 2005;The Enzo Collaboration et al, 2013;Fryxell et al, 2000;Teyssier, 2002), as well as other well-known and tested codes that are not necessarily public (e.g. gasoline, art and arepo; Wadsley et al, 2004;Kravtsov, 1999;Springel, 2010) 26 The physics included in hydrodynamic cosmological simulations is varied even among a common set of codes, and is certainly extremely diverse when considering simulations run with different codes.…”

Formation of cold filaments from colliding superbubbles

“…High-resolution numerical simulations (maximum resolution of 0.1 pc) have been performed with the hydrodynamical Adaptive Mesh refinement (AMR) code RAMSES Teyssier(2002), in two and three dimensions. The time-dependent energy and mass input from OB associations, as calculated by Voss et al (2009) is implemented in the code as a source term in the energy and in the mass equations following a reference table.…”