Baryonic Features in the Matter Transfer Function

We provide scaling relations and tting formulae for adiabatic cold dark matter cosmologies that account for all baryon e ects in the matter transfer function to better than 10% in the large-scale structure regime. They are based upon a physically well-motivated separation of the e ects of acoustic oscillations, Compton drag, velocity overshoot, baryon infall, adiabatic damping, Silk damping, and cold dark matter growth suppression. We also nd a simpler, more accurate, and better motivated form for the zero-baryon transfer function than previous works. These descriptions are employed to quantify the amplitude and location of baryonic features in linear theory. While baryonic oscillations are prominent if the baryon fraction the main e ect in more conventional cosmologies is a sharp