The E-MOSAICS Project: simulating the formation and co-evolution of galaxies and their star cluster populations

摘要

We introduce the MOdelling Star cluster population Assembly In CosmologicalSimulations within EAGLE (E-MOSAICS) project. E-MOSAICS incorporates modelsdescribing the formation, evolution and disruption of star clusters into theEAGLE galaxy formation simulations, enabling the examination of theco-evolution of star clusters and their host galaxies in a fully cosmologicalcontext. A fraction of the star formation rate of dense gas is assumed to yielda cluster population; this fraction, and the population's initial properties,are governed by the physical properties of the natal gas. The subsequentevolution and disruption of the entire cluster population is followedaccounting for two-body relaxation, stellar evolution, and gravitational shocksinduced by the local tidal field. This introductory paper presents a detaileddescription of the model and initial results from a suite of 10 simulations of$\sim L^\star$ galaxies with disc-like morphologies at $z=0$. The simulationsbroadly reproduce key observed characteristics of young star clusters andglobular clusters (GCs), without invoking separate formation mechanisms foreach population. The simulated GCs are the surviving population of massiveclusters formed at early epochs ($z\gtrsim1-2$), when the characteristicpressures and surface densities of star-forming gas were significantly higherthan observed in local galaxies. We examine the influence of the star formationand assembly histories of galaxies on their cluster populations, finding that(at similar present-day mass) earlier-forming galaxies foster a more massiveand disruption-resilient cluster population, while galaxies with late mergersare capable of forming massive clusters even at late cosmic epochs. (Abridged)