Generating approximate halo catalogues for blind challenges in precision cosmology
Abstract
We present a method for generating suites of dark matter halo catalogues with only a few N-body simulations, focusing on making small changes to the underlying cosmology of a simulation with high precision. In the context of blind challenges, this allows us to re-use a simulation by giving it a new cosmology after the original cosmology is revealed. Starting with full N-body realizations of an original cosmology and a target cosmology, we fit a transfer function that displaces haloes in the original so that the galaxy/HOD power spectrum matches that of the target cosmology. This measured transfer function can then be applied to a new realization of the original cosmology to create a new realization of the target cosmology. For a 1 per cent change in σ8, we achieve 0.1 per cent accuracy to k = 1 h Mpc^{-1} in the real-space power spectrum; this degrades to 0.3 per cent when the transfer function is applied to a new realization. We achieve similar accuracy in the redshift-space monopole and quadrupole. In all cases, the result is better than the sample variance of our 1.1 h^{-1} Gpc simulation boxes.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 2019
- DOI:
- 10.1093/mnras/stz600
- arXiv:
- arXiv:1902.09475
- Bibcode:
- 2019MNRAS.485.2407G
- Keywords:
-
- methods: numerical;
- large-scale structure of Universe;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 15 pages, 6 figures. Comments welcome!