The WISE Catalog of Galactic HII Regions
  Using data from the all-sky Wide-Field Infrared Survey Explorer (WISE)
satellite, we made a catalog of over 8000 Galactic HII regions and HII region
candidates by searching for their characteristic mid-infrared (MIR) morphology.
WISE has sufficient sensitivity to detect the MIR emission from HII regions
located anywhere in the Galactic disk. We believe this is the most complete
catalog yet of regions forming massive stars in the Milky Way. Of the ~8000
cataloged sources, ~1500 have measured radio recombination line (RRL) or
H$\alpha$ emission, and are thus known to be HII regions. This sample improves
on previous efforts by resolving HII region complexes into multiple sources and
by removing duplicate entries. There are ~2500 candidate HII regions in the
catalog that are spatially coincident with radio continuum emission. Our
group's previous RRL studies show that ~95% of such targets are HII regions. We
find that ~500 of these candidates are also positionally associated with known
HII region complexes, so the probability of their being bona fide HII regions
is even higher. At the sensitivity limits of existing surveys, ~4000 catalog
sources show no radio continuum emission. Using data from the literature, we
find distances for ~1500 catalog sources, and molecular velocities for ~1500
HII region candidates.
