Primordial non-Gaussianities in the intergalactic medium

Abstract

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-alpha 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 f(NL) = +/- 100 when compared to a standard Lambda cold dark matter cosmology with f(NL) = 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 similar to 4 (for f(NL) = +/- 100),significantly larger than deviations of similar to 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-alpha forest could be possible with future data sets.