Formation of extragalactic Star Clusters

Abstract

The outskirts of galaxies show their beauty by an assembly of Globular Clusters and satellite galaxies, but also by interactions with their environment. Galaxies in clusters experience dynamical effects by mutual encounters and by the intra-cluster gas. This latter exerts a drag to remove gas from the outskirts. These stripped clouds are capable to form stars and open fundamental questions on astrophysical processes, as e.g. the survival of intergalactic clouds, the star-formation process, the evolution of isolated star clusters, etc. Our studies target at star clusters around the Virgo cluster spiral galaxy NGC 4254, observed within the VESTIGE survey. 60 young clusters are identified in the GALEX/FUV with different masses, ages, and separations from the mature galactic disk. Only half of them are also emitting H-alpha as long as the clusters are still encompassed by gas until ram pressure strips it off leading to star-formation quenching and LyC escape.