The initial mass function and stellar birthrate in the solar neighborhood

The paper examines the initial mass function (IMF) and time history of the stellar birthrate in the solar neighborhood under the assumption of a time-independent IMF over the lifetime of the galactic disk. All relevant observational quantities and the associated uncertainties are discussed. Also discussed are IMFs derived for a range of birthrate histories consistent with the continuity constraint. Finally, the study summarizes observational and theoretical arguments concerning the basic assumptions that the IMF is time independent and a continuous function of mass.