The Effects of Local Primordial Non-Gaussianity on the Formation and Evolution of Galaxies

TL;DR

This study uses high-resolution simulations to explore how local primordial non-Gaussianity influences galaxy formation, revealing that strong non-Gaussian signals can lead to earlier structure formation and more massive high-redshift galaxies.

Contribution

It provides the first detailed simulation-based analysis of local primordial non-Gaussianity effects on galaxy formation and evolution across cosmic time.

Findings

Large NG ($f_{NL} \,\gtrsim\, 10^3$) causes earlier structure collapse and more massive high-redshift galaxies.

Smaller NG ($f_{NL} \,\lesssim\, 10^2$) has a weaker impact on galaxy formation.

High-redshift objects like early galaxies and quasars can help constrain primordial NG.

Abstract

Thanks to the rapid progress in precision cosmology in the last few years, we now have access to physical observables that may constrain the theory of inflation through the non-Gaussianity (NG) signatures in the cosmic microwave background radiation and the distribution of large-scale structure. Numerical modeling of the NG signals from different inflation models is essential to correctly interpret current and near future data from large-scale structure surveys. In this study, we use high-resolution cosmological hydrodynamical simulations to investigate the effects of primordial NG on the formation and evolution of galaxies from the cosmic dawn to the present day. Focusing on the local type primordial NG, we find that it may affect the formation history of stars and black holes in galaxies, and their distribution. Compared to the Gaussian case, large non-Gaussian potential with $f_{NL} \gtrsim 10^3$ leads to earlier collapse of the first structures, more massive galaxies especially at high redshifts, stronger clustering of galaxies, and higher halo bias. However, for smaller NG with $f_{NL} \lesssim 10^2$, the effect is significantly weaker. Observations of the distribution and properties of high-redshift, rare objects such as the first galaxies and quasars may provide further constraints on the primordial NG.