http://arxiv.org/abs/1811.09504
We perform an ensemble of cosmological $N$-body simulations with $2048^3$ particles for 101 cosmological models within a flat $w$CDM cosmology framework sampled based on a maximin-distance Sliced Latin Hypercube Design. By using the outputs of $N$-body simulations and the halo catalogs extracted in the range of $z=[0,1.48]$, we develop an emulator, Dark Emulator, which enables fast and accurate computations of halo clustering quantities, the halo mass function, halo-matter cross-correlation, and halo auto-correlation as a function of halo masses, redshift, separations and cosmological models, based on the Principal Component Analysis and the Gaussian Process Regression for the large-dimensional input and output data vector. We use a validation set of $N$-body simulations for cosmological models, which are not used in training the emulator, to assess the performance of the emulator. We show that, for typical halos hosting CMASS galaxies in the Sloan Digital Sky Survey, the emulator predicts the halo-matter cross correlation, relevant for galaxy-galaxy weak lensing, with an accuracy better than $2\%$ and the halo auto-correlation, relevant for galaxy clustering correlation, with an accuracy better than $4\%$. We give several demonstrations of the emulator. For instance, the emulator outputs can be used to study properties of halo mass density profiles such as the mass-concentration relation and splashback radius and their cosmology and redshift dependences. We also show that the emulator outputs can be combined with an analytical prescription of halo-galaxy connection such as the halo occupation distribution at the equation level, instead of using the mock catalogs, to make accurate predictions of galaxy clustering statistics such as the galaxy-galaxy weak lensing and the projected correlation function for any model within the $w$CDM cosmologies, with a CPU time of a few seconds.
T. Nishimichi, M. Takada, R. Takahashi, et. al.
Mon, 26 Nov 18
9/100
Comments: 42 pages, 43 figures; abstract abridged to meet arXiv requirements
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