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arXiv · 1311.6444

Cosmic Emulation: Fast Predictions for the Galaxy Power Spectrum

Juliana Kwan·Katrin Heitmann·Salman Habib·Nikhil Padmanabhan·Hal Finkel·Nick Frontiere·Adrian Pope
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Abstract

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.

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Juliana Kwan, Katrin Heitmann, Salman Habib, Nikhil Padmanabhan, Hal Finkel, Nick Frontiere, Adrian Pope. 2015-08-16. Cosmic Emulation: Fast Predictions for the Galaxy Power Spectrum. https://doi.org/10.1088/0004-637x%2F810%2F1%2F35

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