The halo occupation distribution (HOD) approach has proven to be an effective method for modeling galaxy clustering and bias. In this approach, galaxies of a given type are probabilistically assigned to individual halos in N-body simulations. In this paper, we present a fast emulator for predicting the fully nonlinear galaxy power spectrum over a range of freely specifiable HOD modeling parameters. The emulator is constructed using results from 100 HOD models run on a large LCDM N-body simulation, with Gaussian Process interpolation applied to a PCA-based representation of the galaxy power spectrum. The total error is currently ~3% (~2% in the simulation and ~1% in the emulation process) from z=1 to z=0, over the considered parameter range. We use the emulator to investigate parametric dependencies in the HOD model, as well as the behavior of galaxy bias as a function of HOD parameters. The emulator is publicly available at http://www.hep.anl.gov/cosmology/CosmicEmu/emu.html.
@article{arxiv.1311.6444,
title = {Cosmic Emulation: Fast Predictions for the Galaxy Power Spectrum},
author = {Juliana Kwan and Katrin Heitmann and Salman Habib and Nikhil Padmanabhan and Hal Finkel and Nick Frontiere and Adrian Pope},
journal= {arXiv preprint arXiv:1311.6444},
year = {2017}
}
Comments
Replaced to match published version. The emulator can be downloaded at http://www.hep.anl.gov/cosmology/CosmicEmu/emu.html