2024A&A...689A.339G

We present Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm continuum and CO (2-1) line emission observations toward the high-mass star formation region DR21. Five new continuum sources are found. We identify 18 outflow streamers detected in CO emission that radially arises from a common origin. The velocity spread of the outflow streamers ranges between -100 and +70 km s^–1. The radial velocities of each outflow roughly follow linear gradients (Hubble-Lemaître-like expansion motions). Using the CO emission of the whole ensemble of streamers, we estimate a total outflow mass of 120-210 M_⊙. Additionally, we derived the dynamical age (8600 yr), momentum (∼10³M_⊙ km s^–1), and kinetic energy (∼10⁴⁸ erg) of the outflow. The morphology and kinematics presented by the CO outflow streamers confirm an explosive dispersal outflow at the heart of DR21. Five dispersal explosive outflows associated with massive star-forming regions have been confirmed in our Galaxy (Orion BN/KL, G5.89-0.39, S106-IR, IRAS 16076-5134, and IRAS 12326-6245). However, their occurrence frequency in the Galaxy and their origin are still uncertain.