Supernovae and galactic outflows

Supernovae associated with the death of massive stars play a fundamental role in galaxies. They produce and spread metals, accelerate cosmic rays and drive turbulence in the interstellar medium (ISM). Supernova heat and stir the ISM, thereby suppressing the amount of cold gas and hence star formation. A problem with isolated supernovae is that they suffer catastrophic radiative losses by 1 Myr (million years), a time much shorter than galactic dynamical timescales (10-100 Myr). However, most stars form in compact clusters, and supernovae go off together in space and time forming a superbubble that can retain energy for longer timescales. Intense star formation in galactic centers can cause superbubble-driven galactic outflows. I will describe our work on superbubbles and galactic winds, and their various applications, ranging from Fermi Bubbles in Milky Way to the escape of ionizing photons from galaxies.