Authors:
Klypin A., Prada F., Yepes G., Heß S., Gottlöber S.
Journal:
Monthly Notices of the Royal Astronomical Society
Abstract:
Accurate predictions of the abundance and clustering of dark matter haloes play a key role in testing the standard cosmological model. Here, we investigate the accuracy of one of the leading methods of connecting the simulated dark matter haloes with observed galaxies-the halo abundance matching (HAM) technique.We show how to choose the optimal values of the mass and force resolution in large volume N-body simulations so that they provide accurate estimates for correlation functions and circular velocities for haloes and their subhaloes-crucial ingredients of the HAM method. At the 10 per cent accuracy, results converge for-50 particles for haloes and-150 particles for progenitors of subhaloes. In order to achieve this level of accuracy a number of conditions should be satisfied. The force resolution for the smallest resolved (sub)haloes should be in the range (0.1-0.3)rs, where rs is the scale radius of (sub)haloes. The number of particles for progenitors of subhaloes should be-150. We also demonstrate that the two-body scattering plays a minor role for the accuracy of N-body simulations thanks to the relatively small number of crossing-times of dark matter in haloes, and the limited force resolution of cosmological simulations. © 2015 The Authors.
Keywords:
Cosmology: theory; Large-scale structure of universe; Methods: numerical