Journal Article

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

Vincent Desjacques, Uroš Seljak and Ilian T. Iliev

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 396, issue 1, pages 85-96
Published in print June 2009 | ISSN: 0035-8711
Published online June 2009 | e-ISSN: 1365-2966 | DOI:
Scale-dependent bias induced by local non-Gaussianity: a comparison to N-body simulations

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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.

Keywords: gravitation; galaxies: haloes; cosmology: theory; dark matter

Journal Article.  7911 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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