Evolution and excitation conditions of outflows in high-mass star-forming regions

Context. Theoretical models suggest that massive stars form via disk-mediated accretion in a similar fashion to low-mass stars. In this scenario, bipolar outflows ejected along the disk axis play a fundamental role, and their study can help characterize the different evolutionary stages involved in the formation of a high-mass star. A recent study toward massive molecular outflows has revealed a decrease in the SiO line intensity as the object evolves.