Mid-Infrared Selection of Active Galactic Nuclei with the Wide-Field Infrared Survey Explorer. II. Properties of WISE-Selected Active Galactic Nuclei in the NDWFS Bo\"otes Field

Understand

Stern et al.(2012) presented a study of WISE selection of AGN in the 2 deg^2 COSMOS field, finding that a simple criterion W1-W2>=0.8 provides a highly reliable and complete AGN sample for W2<15.05, where the W1 and W2 passbands are centered at 3.4 and 4.6 microns, respectively.

• Here we extend this study using the larger 9 deg^2 NOAO Deep Wide-Field Survey Bootes field which also has considerably deeper WISE observations than the COSMOS field, and find that this simple color-cut significantly loses reliability at fainter fluxes.
• We define a modified selection criterion combining the W1-W2 color and the W2 magnitude to provide highly reliable or highly complete AGN samples for fainter WISE sources.
• In particular, we define a color-magnitude cut that finds 130+/-4 deg^-2 AGN candidates for W2<17.11 with 90% reliability.