Classification Study of WISE Infrared Sources: Identification of
  Candidate Asymptotic Giant Branch Stars
  In the WISE all-sky source catalogue there are 76 million mid-infrared (MIR)
point sources that were detected at the first three WISE bands and have
association with only one 2MASS near-IR source within 3 arcsec. We search for
their identifications in the SIMBAD database and find 3.2 million identified
sources. Based on these known sources, we establish three criteria for
selecting candidate AGB stars in the Galaxy, which are three defined occupation
zones in a color-color diagram, Galactic latitude |gb|< 20 deg, and "corrected"
WISE third-band W3c < 11. Applying these criteria to the WISE+2MASS sources,
1.37 million of them are selected. We analyze the WISE third-band W3
distribution of the selected sources, and further establish that W3 < 8 is
required in order to exclude a large fraction of normal stars in them. We
therefore find 0.47 million candidate AGB stars in our Galaxy from the WISE
source catalogue. Using W3c, we estimate their distances and derive their
Galactic distributions. The candidates are generally located around the
Galactic center uniformly, with 68% (1-sigma) of them within approximately 8
kpc. We discuss that optical spectroscopy can be used to verify the C-rich AGB
stars in our candidates, and they will be good targets for the LAMOST survey
that is planned to start from fall of 2012.
