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The effect of local non-Gaussianity on the matter bispectrum at small scales

Figueroa, D. G.
Sefusatti, E.
Published in Journal of Cosmology and Astroparticle Physics. 2012, vol. 2012, no. 08, p. 036-036
Abstract We compute the matter bispectrum in the presence of primordial local non-Gaussianity over a wide range of scales, including the very small nonlinear ones. We use the Halo Model approach, considering non-Gaussian corrections to the halo profiles, the halo mass function and the bias functions. We compare our results in the linear and mildly nonlinear scales to a large ensemble of Gaussian and non-Gaussian numerical simulations. We consider both squeezed and equilateral configurations, at redshift z = 0 and z = 1. For z = 0, the deviations between the Halo Model and the simulations are smaller than 10% in the squeezed limit, both in the Gaussian and non-Gaussian cases. The Halo Model allows to make predictions on scales much smaller than those reached by numerical simulations. For local non-Gaussian initial conditions with a parameter fNL = 100, we find an enhancement of the bispectrum in the squeezed configuration k = k3 = k2 >> k1 ~ 0.01h−1Mpc, of ~ 15% and ~ 25% on scales k ~ 1h−1Mpc, at z = 0 and z = 1 respectively. This is mainly due to the non-Gaussian corrections in the linear bias. Finally we provide a very simple expression valid for any scenario, i.e. for any choice of the halo profile, mass and bias functions, which allow for a fast evaluation of the bispectrum on squeezed configurations.
Keywords Power spectrumCosmological simulationsGalaxy clustersNon-gaussianity
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FIGUEROA, D. G. et al. The effect of local non-Gaussianity on the matter bispectrum at small scales. In: Journal of Cosmology and Astroparticle Physics, 2012, vol. 2012, n° 08, p. 036-036. https://archive-ouverte.unige.ch/unige:36506

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Deposited on : 2014-05-12

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