I will discuss cosmic rays (particles with energies greater than 1 GeV) in the context of galaxy formation. Cosmic rays are know to be a significant source of pressure within the interstellar medium of the Milky Way, roughly in equipartition with thermal, magnetic, and turbulent pressures. Despite this, the dynamical impact of CRs on galaxy formation has been largely unstudied in numerical simulations until the past few years. I will summarize this work to date, which indicate cosmic rays may be important in driving galactic outflows, and describe my own simulation work in this area which in addition to galactic outflows, indicate cosmic rays may play a role in regulating the phase structure of the Milky Way’s thermal gas.
