A large fraction of stars forms in clusters containing high-mass stars, which affect the local environment and the Galaxy itself. Several studies have been carried out in past years to shed light on the formation of high-mass stars, in which several physical processes (e.g. gravity, turbulence, magnetic field, feedback, gas flows from larger scales) play a role. However, a full understanding of the fragmentation process and its role in allowing high-mass stars to collect material up to their final mass is still elusive.

ALMAGAL will observe for the first time a statistically significant and complete sample of high-mass star-forming regions with the ALMA interferometer to answer some of the open questions in the field of clump fragmentation and of formation of high-mass stars.

The project targets an unprecedented large sample of more than 1000 dense clumps, in all the evolutionary stages of high-mass star formation, observed with a homogeneous high linear resolution of  ~1000 AU. The clumps have been selected from the Hi-Gal survey to have masses larger than 500 M_Sun and are spread from the near tip of the Galactic Bar to the outskirts of the Milky Way, to study if and how the fragmentation process is influenced by the different environmental conditions inside the Galaxy.

The analysis of the ALMAGAL sample, covering all the evolutionary stages of star formation and different ambient conditions in the Galaxy, and the comparison of these observations with the results of simulations will allow us to make a significant step forward in the comprehension of the star-formation process and fragmentation.