From formation to quenching: The role of overdensities in high-redshift galaxy evolution

Abstract

This study investigates the evolution of galaxies within 13 overdensities at redshifts 3 < z < 4, providing critical insights into galaxy formation and evolution in dense environments. Key findings include the observation that passive galaxies in these protoclusters are rare, with only two overdensities containing them. These passive galaxies are distinguished by their redder color, greater mass, older age, lower star formation rates, and higher stellar density. A notable discovery is the exclusive presence of AGNs in overdensities with passive galaxies, hinting at a potential correlation between AGN activity and the presence of passive galaxies. Spatial analysis underlines that passive galaxies predominantly occupy the highest density peaks within these overdensities. Comparisons with TNG300 simulations suggest that protoclusters with early passive galaxies are likely to evolve with a higher fraction of passive galaxies at lower redshifts. The estimated Dark Matter Halo values for these overdensities correspond with protocluster expectations. This research significantly advances our understanding of the role of dense environments in galaxy evolution, particularly highlighting the development of passive galaxies within protoclusters and offering new perspectives on environmental impacts on galactic evolution and early universe structure formation.