The imprint of cosmological non-Gaussianities on primordial structure formation

TL;DR

This study uses numerical simulations to explore how primordial non-Gaussianities influence early star and galaxy formation, affecting timing, feedback processes, and chemical enrichment in the universe.

Contribution

It provides new insights into the effects of primordial non-Gaussianities on structure formation and feedback mechanisms during the universe's first billion years.

Findings

Higher fnl leads to earlier star formation and feedback.

Metal enrichment is significantly faster in high-fnl models.

Gas properties become more concentrated with larger fnl at early times.

Abstract

We study via numerical N-body/SPH chemistry simulations the effects of primordial non-Gaussianities on the formation of the first stars and galaxies, and investigate the impact of supernova feedback in cosmologies with different fnl. Density distributions are biased to higher values, so star formation and the consequent feedback processes take place earlier in high-fnl models and later in low-fnl ones. Mechanical feedback is responsible for shocking and evacuating the gas from star forming sites earlier in the highly non-Gaussian cases, because of the larger bias at high densities. Chemical feedback translates into high-redshift metal filling factors that are larger by some orders of magnitude for larger fnl, but that converge within one Gyr, for both population III and population II-I stellar regimes. The efficient enrichment process, though, leads to metallicities > 0.01 Zsun by redshift ~9, almost independently from fnl. The impact of non-Gaussianities on the formation of dark-matter haloes at high redshift is directly reflected in the properties of the gas in these haloes, as models with larger fnl show more concentrated gas profiles at early times. Non-Gaussian signatures in the gas behaviour are lost after the first feedback takes place and introduces a significant degree of turbulence and chaotic motions.