Gas distribution, metal enrichment and baryon fraction in Gaussian and non-Gaussian universes

We study the cosmological evolution of baryons in universes with and without primordial non-Gaussianities via N-body/hydrodynamical simulations, including gas cooling, star formation, stellar evolution, chemical enrichment from both population III and population II regimes, and feedback effects. We find that large f(NL) values for non-Gaussianities can alter the gas probability distribution functions, the metal pollution history, the halo baryon, gas and stellar fractions, mostly at early times. More precisely, (i) non-Gaussianities lead to an earlier evolution of primordial gas, structures and star formation; (ii) metal enrichment starts earlier (with respect to the Gaussian scenario) in non-Gaussian models with larger f(NL); (iii) gas fractions within the haloes are not significantly affected by the different values of f(NL), with deviations of similar to 1-10%; (iv) the stellar fraction is quite sensitive to non-Gaussianities at early times, with discrepancies reaching up to a factor of similar to 10 at very high z, and rapidly converging at low z; (v) the trends at low redshift are independent from f(NL): they are mostly led by the ongoing baryonic evolution and by the feedback mechanisms, which determine a similar to 25-30% discrepancy in the baryon fraction of galaxy groups/clusters with respect to the cosmic values; (vi) non-Gaussianity impacts on the cluster x-ray emission or on the Sunyaev-Zeldovic effect(s) are expected to be not very large and dominated by feedback mechanisms, whereas some effects on the 21 cm emission can be expected at early times; (vii) in order to address non-Gaussianities in the cosmological structure contest, high-redshift (z similar to 10) investigations are required: first stars, galaxies, quasars and gamma-ray bursts may be potential cosmological probes of non-Gaussianities.