The Wise Catalog of Galactic H Ii Regions

Using data from the all-sky Wide-Field Infrared Survey Explorer ( WISE ) satellite, we made a catalog of over 8000 Galactic H ii regions and H ii region candidates by searching for their characteristic mid-infrared (MIR) morphology. WISE has sufficient sensitivity to detect the MIR emission from H ii 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 Hα emission, and are thus known to be H ii regions. This sample improves on previous efforts by resolving H ii region complexes into multiple sources and by removing duplicate entries. There are ∼2500 candidate H ii 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 H ii regions. We find that ∼500 of these candidates are also positionally associated with known H ii region complexes, so the probability of their being bona fide H ii 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 ∼1500H ii region candidates.