Journal Article

Primordial non-Gaussianities in the intergalactic medium

M. Viel, E. Branchini, K. Dolag, M. Grossi, S. Matarrese and L. Moscardini

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 393, issue 3, pages 774-782
Published in print March 2009 | ISSN: 0035-8711
Published online February 2009 | e-ISSN: 1365-2966 | DOI:
Primordial non-Gaussianities in the intergalactic medium

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We present results from the first high-resolution hydrodynamical simulations of non-Gaussian cosmological models. We focus on the statistical properties of the transmitted Lyman-α flux in the high-redshift intergalactic medium. Imprints of non-Gaussianity are present and are larger at high redshifts. Differences larger than 20 per cent at z > 3 in the flux probability distribution function for high-transmissivity regions (voids) are expected for values of the non-linearity parameter fNL=±100 when compared to a standard Λ cold dark matter cosmology with fNL= 0. We also investigate the one-dimensional flux bispectrum: at the largest scales (corresponding to tens of Mpc), we expect deviations in the flux bispectrum up to 20 per cent at z∼ 4 (for fNL=±100), significantly larger than deviations of ∼3 per cent in the flux power spectrum. We briefly discuss possible systematic errors that can contaminate the signal. Although challenging, a detection of non-Gaussianities in the interesting regime of scales and redshifts probed by the Lyman-α forest could be possible with future data sets.

Keywords: quasars: absorption lines; cosmology: observations; cosmology: theory

Journal Article.  6462 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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