The dual nature of (stellar) feedback in galaxy evolution

Feedback processes are central to the evolution of galaxies since they regulate the baryon flow to and from them. However, these processes are extremely difficult to simulate owing to large range of spatial scales that need to be modelled. In the cosmological context there is a general consensus on feedback being a “negative” process that limits the conversion of gas into stars by the creation of large-scale outflows. On smaller scales high-resolution simulations have shown that (stellar) feedback can actually promote gas accretion from the hot phase of the CGM (the so-called corona), thus acting as a “positive” feedback mechanism. How these two opposed natures of feedback can co-exist in the current paradigm of galaxy evolution is still not clear. In this talk, I will illustrate the dual nature of feedback processes and its implications for the evolution of galaxies by focusing on the current status of the numerical simulations in which feedback plays a key role