| Description: | Supersonic outflows are ubiquitous in the Universe. They are present in astrophysical sources such as massive stars, supernova remnants, and jets on all scales. The interactions between these outflows trigger a rich phenomenology, as they produce strong shock waves capable of accelerating relativistic particles that, in turn, emit broadband radiation from low radio frequencies up to very energetic gamma rays. I will focus on how radio observations together with theoretical modelling can help us to unveil the physical processes taking place in these sources. In particular, I will present studies of the synchrotron emission associated with colliding stellar winds to exemplify how we can derive physical properties of these systems, such as their mass-loss rates, magnetic field intensity, and particle acceleration efficiency. |
