Target Selection for the Apache Point Observatory Galactic Evolution
  Experiment (APOGEE)
  The Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a
high-resolution infrared spectroscopic survey spanning all Galactic
environments (i.e., bulge, disk, and halo), with the principal goal of
constraining dynamical and chemical evolution models of the Milky Way. APOGEE
takes advantage of the reduced effects of extinction at infrared wavelengths to
observe the inner Galaxy and bulge at an unprecedented level of detail. The
survey's broad spatial and wavelength coverage enables users of APOGEE data to
address numerous Galactic structure and stellar populations issues. In this
paper we describe the APOGEE targeting scheme and document its various target
classes to provide the necessary background and reference information to
analyze samples of APOGEE data with awareness of the imposed selection criteria
and resulting sample properties. APOGEE's primary sample consists of ~100,000
red giant stars, selected to minimize observational biases in age and
metallicity. We present the methodology and considerations that drive the
selection of this sample and evaluate the accuracy, efficiency, and caveats of
the selection and sampling algorithms. We also describe additional target
classes that contribute to the APOGEE sample, including numerous ancillary
science programs, and we outline the targeting data that will be included in
the public data releases.
