How galaxies acquire their stellar mass at redshift z>5: An overview from a semi-empirical point of view
Hao Fu (Fudan University, Shanghai)
Tuesday 29/09/2026 @ 14:30, Sala Antonio Sollima (IV piano Battiferro)
The new data from the ongoing observing facilities have revolutionized our view of the early Universe, having detected luminous galaxies at unprecedent redshifts. However, the formation and evolution of these objects are still unclear from the theoretical side and has enhanced the urge for data-driven models to bridge the gap between observations and theoretical expectations. Here, I present the results on the stellar mass growth of galaxies from our cosmological semi-empirical model. We simulate galaxy star formation histories via abundance matching using the most up-to-date observed luminosity functions from a wide range of high-z surveys, including JWST and Euclid. Mergers are added by initialising satellites via accurate stellar mass-halo mass relations on top of merger trees from N-body simulations, setting constraints on galaxy merger rates. In this presentation, I will show how our cosmological model can fairly reproduce the observed galaxy abundances with minimal assumptions, and their star formation efficiencies within a LCDM framework. I will also show what are the relative contribution of mergers on the galaxy stellar mass growth against in situ star formation. Finally, I will discuss how mergers can potentially impact the quenching of massive galaxies at the same redshifts and reproduce the observed number densities and fractions of quiescent galaxies.