The mass-Peak Patch algorithm for fast generation of deep all-sky dark matter halo catalogues and its N-body validation
Abstract
We present a detailed description and validation of our massively parallel update to the mass-Peak Patch method, a fully predictive initial-space algorithm to quickly generate dark matter halo catalogues in very large cosmological volumes. We perform an extensive systematic comparison to a suite of N-body simulations covering a broad range of redshifts and simulation resolutions, and find that, without any parameter fitting, our method is able to generally reproduce N-body results while typically using over 3 orders of magnitude less CPU time, and a fraction of the memory cost. Instead of calculating the full non-linear gravitational collapse determined by an N-body simulation, the mass-Peak Patch method finds an overcomplete set of just-collapsed structures around a hierarchy of density-peak points by coarse-grained (homogeneous) ellipsoidal dynamics. A complete set of mass peaks, or haloes, is then determined by exclusion of overlapping patches, and second-order Lagrangian displacements are used to move the haloes to their final positions and to give their flow velocities. Our results show that the mass-Peak Patch method is well suited for creating large ensembles of halo catalogues to mock cosmological surveys, and to aid in complex statistical interpretations of cosmological models.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- February 2019
- DOI:
- 10.1093/mnras/sty3226
- arXiv:
- arXiv:1810.07727
- Bibcode:
- 2019MNRAS.483.2236S
- Keywords:
-
- large-scale structure of Universe;
- dark matter;
- methods: numerical;
- galaxies: haloes;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 17 pages, 12 figures. Submitted to MNRAS. Comments welcome!