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Scale-dependent bias induced by local non-Gaussianity: a comparison to N-body simulations


Desjacques, V; Seljak, U; Iliev, I T (2009). Scale-dependent bias induced by local non-Gaussianity: a comparison to N-body simulations. Monthly Notices of the Royal Astronomical Society, 396(1):85-96.

Abstract

We investigate the effect of primordial non-Gaussianity of the local fNL type on the auto- and cross-power spectra of dark matter haloes using simulations of the Λ cold dark matter cosmology. We perform a series of large N-body simulations of both positive and negative fNL, spanning the range between 10 and 100. Theoretical models predict a scale-dependent bias correction Δb(k, fNL) that depends on the linear halo bias b(M) . We measure the power spectra for a range of halo mass and redshifts covering the relevant range of existing galaxy and quasar populations. We show that auto- and cross-correlation analyses of bias are consistent with each other. We find that for low wavenumbers with k < 0.03 h Mpc−1 the theory and the simulations agree well with each other for biased haloes with b(M) > 1.5 . We show that a scale-independent bias correction improves the comparison between theory and simulations on smaller scales, where the scale-dependent effect rapidly becomes negligible. The current limits on fNL from Slosar et al. come mostly from very large scales k < 0.01 h Mpc−1 and, therefore, remain valid. For the halo samples with b(M) < 1.5 − 2 , we find that the scale-dependent bias from non-Gaussianity actually exceeds the theoretical predictions. Our results are consistent with the bias correction scaling linearly with fNL.

We investigate the effect of primordial non-Gaussianity of the local fNL type on the auto- and cross-power spectra of dark matter haloes using simulations of the Λ cold dark matter cosmology. We perform a series of large N-body simulations of both positive and negative fNL, spanning the range between 10 and 100. Theoretical models predict a scale-dependent bias correction Δb(k, fNL) that depends on the linear halo bias b(M) . We measure the power spectra for a range of halo mass and redshifts covering the relevant range of existing galaxy and quasar populations. We show that auto- and cross-correlation analyses of bias are consistent with each other. We find that for low wavenumbers with k < 0.03 h Mpc−1 the theory and the simulations agree well with each other for biased haloes with b(M) > 1.5 . We show that a scale-independent bias correction improves the comparison between theory and simulations on smaller scales, where the scale-dependent effect rapidly becomes negligible. The current limits on fNL from Slosar et al. come mostly from very large scales k < 0.01 h Mpc−1 and, therefore, remain valid. For the halo samples with b(M) < 1.5 − 2 , we find that the scale-dependent bias from non-Gaussianity actually exceeds the theoretical predictions. Our results are consistent with the bias correction scaling linearly with fNL.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute for Computational Science
Dewey Decimal Classification:530 Physics
Uncontrolled Keywords:gravitation; galaxies: haloes; cosmology: theory; dark matter
Language:English
Date:June 2009
Deposited On:26 Feb 2010 13:16
Last Modified:05 Apr 2016 13:56
Publisher:Wiley-Blackwell
ISSN:0035-8711
Funders:Swiss National Foundation [200021-116696/1]
Additional Information:The attached file is a preprint (accepted version) of an article published in Monthly Notices of the Royal Astronomical Society. The definitive version is available at www3.interscience.wiley.com
Publisher DOI:10.1111/j.1365-2966.2009.14721.x
Related URLs:http://arxiv.org/abs/0811.2748
Permanent URL: http://doi.org/10.5167/uzh-30877

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