– 26 – Fig. 5.— Left panel: mid-IR color-color distribution of all Photometry Group 3, Variability Level 2 sources in SDWFS. The contours show the distribution of all Photometry Group 3 sources, as described in Figure 4. The Stern et al. (2005) AGN selection region is shown by the dashed wedge, and the modified AGN wedge is shown with the solid line. The stellar box encompasses sources with (stellar) colors near zero. The majority of mid-IR variable objects (76%) are AGNs. Also 11% of objects in the stellar box are variable. Right panel: fraction of Photometry Group 2 sources (e.g., sources lacking reliable [5 . 8] and/or [8 . 0] photometry) that are Variability Level 2 variables as a function of [3 . 6] − [4 . 5] color.