Dynamical signs of a spiral-like structure in the MonR2 hub-filament system

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 towards MonocerosR2 (hereafter MonR2) star-forming region with the main goal of building a picture of its global dynamical properties. MonR2 is 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 the total 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 converging towards the central region where the most massive stars form. The spiral-like structure presents signs of rotation and infall motions, posing the question of whether these structures are required in the formation of massive stars or are an outcome of the accretion process.