High-mass stars drive the physical and chemical evolution of the Universe. However, the origin of these massive objects is largely controversial. Three key questions remain under debate: a) Which physical processes determine the formation of high-mass stars? b) How do these stars get their large masses? c) Do high-mass stars form in a similar way to their low-mass counterparts?

Galactic surveys link the origin of high-mass stars to the initial properties of their gas embryos. Using the Atacama Large Millimeter Array (ALMA), Hacar et al (2018) recently proved the existence of a new and fundamental filamentary organization of the gas within the Orion Nebula, the nearest high-mass star-forming region. After leading this key discovery, EMERGE proposes to investigate the formation of high-mass stars as an emergent process in complex systems. In this novel scenario massive stars are created naturally by the internal interactions within networks of filaments of increasing density. To fully characterize this ground-breaking approach, this project will carry out the first systematic study of (1) the substructure, (2) internal interactions, and (3) dynamical evolution of these filamentary systems across the Milky Way.

EMERGE will survey a homogeneous ALMA sample of massive filamentary networks, the largest of its kind, extracted from the first intensive exploitation of its public archive. These observational results will be tested against state-of-the-art simulations using a new generation of analysis tools. The ultimate goal of this project is to statistically quantify how unique multi-scale phenomena generated in these filamentary systems, such as collisions, mergers, and self-gravity, determine the initial conditions for the formation of high-mass stars. This ERC-StG project will solve a current challenging dichotomy in star formation theory. In combination with low-mass studies, EMERGE will provide a major step towards a comprehensive model of star formation under one filamentary paradigm.