Generating Approximate Halo Catalogs for Blind Challenges in Precision Cosmology

Abstract

We present a method for generating suites of dark-matter halo catalogs 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 reuse 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 halos 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% change in ${\sigma }_8$, we achieve 0.1% accuracy to $k=1h{\mathrm{Mpc}}^{-1}$ in the real-space power spectrum; this degrades to 0.3% 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 $1.1h^{-1}\mathrm{Gpc}$ simulation boxes.

arXiv comment15 pages, 6 figures. Comments welcome!

References in corpus (8)

• Large-Scale Structure of the Universe and Cosmological Perturbation Theory
• The Rockstar Phase-Space Temporal Halo Finder and the Velocity Offsets of Cluster Cores
• Correcting for the alias effect when measuring the power spectrum using FFT
• The overdensity and masses of the friends-of-friends halos and universality of the halo mass function
• The Mira-Titan Universe: Precision Predictions for Dark Energy Surveys
• The Abacus Cosmos: A Suite of Cosmological N-body Simulations
• Improving Initial Conditions for Cosmological $N$-Body Simulations
• Remapping dark matter halo catalogues between cosmological simulations

Cited by in corpus (3)

• The $\text{Abacus}$ Cosmological $N$-body Code
• The Completed SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: N-body Mock Challenge for the Quasar Sample
• On the primordial information available to galaxy redshift surveys