The study of the filamentary structures in massive star-forming regions is undergoing a revolution, thanks in large part to the unprecedented high angular resolution and sensitivity that ALMA provides. We have used ALMA to conduct an observational study of two massive filaments and a hub-filament system with the main goal of building a picture of their global dynamical properties and fragmentation. We present the results for the Monoceros R2 (hereafter MonR2) molecular cloud, one of the nearest and clearest examples of a hub-filament system. The central hub hosts a cluster of massive protostars associated with an expanding HII region, where a number of filaments are converging. We have estimated total the mass accretion rate along the filaments on the order of 10^(-3) Msun/yr. Inside the central hub, the filaments appear twisted forming a spiral-like structure, with signs of rotation and infall motions. Overall, the hub-filament system in MonR2 suggests a scenario of non-isotropic global collapse, forming a massive stellar cluster. We also present our results for G357, which is a massive filament similar to the integral shaped filament (ISF) in Orion A, but shows remarkably low star formation activity. The comparison of the fragmentation and dynamics of G357 and the ISF enables us to address the early evolution of massive filaments.
Local contact: P. Didelon
Organization: V. Lebouteiller