Halo mass function and scale-dependent bias from N-body simulations with non-Gaussian initial conditions

By A. Pillepich, C. Porciani, Oliver Hahn. 2008

197 citations recorded by the source corpus.

We perform a series of high-resolution N-body simulations of cosmological structure formation starting from Gaussian and non-Gaussian initial conditions. We adopt the best-fitting cosmological parameters from the third- and fifth-year data releases of the Wilkinson Microwave Anisotropy Probe, and we consider non-Gaussianity of the local type parametrized by eight different values of the non-linearity parameter f NL . Building upon previous work based on the Gaussian case, we show that, when expressed in terms of suitable variables, the mass function of friends-of-friends haloes is approximately universal (i.e. independent of redshift, cosmology and matter transfer function) to good precision (nearly 10 per cent) also in non-Gaussian scenarios. We provide fitting formulae for the high-mass end (M > 10 13 h -1 M ⊙ ) of the universal mass function in terms of f NL , and we also present a non-universal fit in terms of bothfN L and z to be used for applications requiring higher accuracy. For Gaussian initial conditions, we extend our fit to a wider range of halo masses (M > 2.4 x 10 10 h -1 M ⊙ ) and we also provide a consistent fit of the linear halo bias. We show that, for realistic values of f NL , the matter power spectrum in non-Gaussian cosmologies departs from the Gaussian 1 by up to 2 per cent on the scales where the baryonic-oscillation features are imprinted on the two-point statistics. Finally, using both the halo power spectrum and the halo-matter cross spectrum, we confirm the strong k-dependence of the halo bias on large scales (k < 0.05 h Mpc 1- ) which was already detected in previous studies. However, we find that commonly used parametrizations based on the peak-background split do not provide an accurate description of our simulations which present extra dependencies on the wavenumber, the non-linearity parameter and, possibly, the clustering strength. We provide an accurate fit of the simulation data that can be used as a benchmark for future determinations of f NL with galaxy surveys.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/1a34d1be9bc8ba83cd949e95e6c4b712fe2728e5

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Citations in the corpus

Probing primordial non-Gaussianity with SKA galaxy redshift surveys: a fully relativistic analysis (2014, methodology): “(4) we have used the large-scale structure (LSS) convention for defining fNL, as opposed to the CMB convention (Afshordi & Tolley 2008; Pillepich et al. 2010; Carbone et al. 2008; Grossi et al. 2009).”
Large-scale bias and efficient generation of initial conditions for nonlocal primordial non-Gaussianity (2011, background): “75) on top of the standard prediction [28, 69, 70, 82].”
Cosmology and Fundamental Physics with the Euclid Satellite (2012, background): “The amplitude and shape of the matter power spectrum in the mildly nonlinear regime depend (at a level of a few per cent) on the level of primordial non-Gaussianity (Taruya et al. 2008; Pillepich et al. 2010; Giannantonio and Porciani 2010).”
Primordial non-Gaussianity from the large-scale structure (2010, methodology): “However, while a number of numerical studies of the f loc NL model have confirmed the scaling bκ ( k, f loc NL ) ∝ MR(k)−1 and the redshift dependence ∝D(z)−1 [13, 42, 43, 98], the exact amplitude of the non-Gaussian bias correction remains somewhat debatable.”
GRAVITATIONALLY CONSISTENT HALO CATALOGS AND MERGER TREES FOR PRECISION COSMOLOGY (2011, background): “Similar levels of accuracy are required to be able to distinguish between different values of the primordial non-gaussianity parameter fNL (Pillepich et al. 2010).”
Large-scale non-Gaussian mass function and halo bias: tests on N-body simulations (2009, methodology): “5, the left-hand panel shows the results for Pillepich et al. (2008) (green points) at z = 0.5, and our points for the two closest available output times of our simulation (z = 0.44 and 0.61).”
Constraining primordial non-Gaussianity with future galaxy surveys (2011, methodology): “Similar considerations apply to modifications of the matter power spectrum on small scales induced by PNG (Taruya et al. 2008; Pillepich et al. 2010).”
Primordial Non-Gaussianity and Bispectrum Measurements in the Cosmic Microwave Background and Large-Scale Structure (2010, background): “[140], are consistent with a scale-dependent correction to the linear bias of the form”