The luminosity function of M3

We present a high-precision, large-sample luminosity function (LF) for the Galactic globular duster M3. With a combination of ground-based and Hubble Space Telescope data we cover the entire radial extent of the cluster. The observed LF is well fitted by canonical standard stellar models from the red giant branch (RGB) tip to below the main-sequence turnoff point. Specifically, neither the RGB LF bump nor subgiant branch LF indicate any breakdown in the standard models. On the main sequence we find evidence for a flat initial mass function and for mass segregation due to the dynamical evolution of the cluster.