Institution(s): 1. UC Santa Cruz
Stellar feedback, the injection of energy and momentum by stars, remains one of the largest uncertainties in star cluster formation. Massive stars dramatically affect the surrounding interstellar medium (ISM) through a variety of feedback mechanisms including the direct and dust-reprocessed radiation pressure, and the hot gas shock-heated by stellar winds. These mechanisms can limit star formation efficiencies in massive star clusters (MSCs). For stellar winds, I discuss how we can use observations to constrain a range of kinetic energy loss channels, including radiative cooling, mechanical work on the cold ISM, thermal conduction, heating of dust via collisions by the hot gas, and bulk advection of thermal energy by the hot gas. I demonstrate that the kinetic energy injected by stellar winds is not a significant contributor to stellar feedback. I argue instead that radiation pressure is likely the dominant feedback mechanism in MSCs formed in massive, dense molecular clouds with escape speeds greater than 10 km/s, at least for the ~4 Myr before supernovae begin. Thus simulations of MSC formation require an accurate treatment of the radiation field which captures the first absorption event of stellar irradiation and also follows the diffuse dust-reprocessed radiation field. To this end, we have developed a multi-frequency hybrid radiation scheme in the astrophysical AMR code ORION to be used in such simulations.