The Coyote Universe. I. Precision Determination of the Nonlinear Matter Power Spectrum

• Published in: The Astrophysical journal Vol. 715; no. 1; pp. 104 - 121
• Main Authors: Heitmann, Katrin, White, Martin, Wagner, Christian, Habib, Salman, Higdon, David
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 20.05.2010; IOP
• Subjects: Astronomy; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Earth, ocean, space; Exact sciences and technology; GRAVITATION; MASS RESOLUTION; MATTER; NONLINEAR PROBLEMS; NONLUMINOUS MATTER; RESOLUTION; UNIVERSE; Numerical method; Power spectra; Large-scale structure; methods: numerical; large-scale structure of universe
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/715/1/104

Near-future cosmological observations targeted at investigations of dark energy pose stringent requirements on the accuracy of theoretical predictions for the nonlinear clustering of matter. Currently, N-body simulations comprise the only viable approach to this problem. In this paper, we study various sources of computational error and methods to control them. By applying our methodology to a large suite of cosmological simulations we show that results for the (gravity-only) nonlinear matter power spectrum can be obtained at 1% accuracy out to k {approx} 1 h Mpc{sup -1}. The key components of these high accuracy simulations are precise initial conditions, very large simulation volumes, sufficient mass resolution, and accurate time stepping. This paper is the first in a series of three; the final aim is a high-accuracy prediction scheme for the nonlinear matter power spectrum that improves current fitting formulae by an order of magnitude.