Table 3. Mid-IR Variable Objects in the SDWFS. Variability Variability Old AGN Wedge Modified AGN Wedge Stellar Box Outside a All Abjects a Level σ$_{12}$ Number (fraction/false positive rate $^{b}$) of variable objects: Photometry Group 1 Total ... 43468 76005 45939 144263 474179 2 > 2 746 (1.7%/28%) 1015 (1.3%/33%) 555 (1.2%/58%) 832 (0.6%/71%) 5107 (1.1%/57%) 3 > 3 397 (0.9%/17%) 501 (0.7%/22%) 226 (0.5%/54%) 326 (0.2%/56%) 2208 (0.5%/47%) 4 > 4 246 (0.6%/11%) 293 (0.4%/17%) 102 (0.2%/51%) 156 (0.1%/53%) 1071 (0.2%/44%) Number (fraction/false positive rate $^{b}$) of variable objects: Photometry Group 2 Total ... 29181 54920 18150 113299 213594 2 > 2 598 (2.0%/18%) 774 (1.4%/24%) 133 (0.7%/65%) 512 (0.5%/74%) 1557 (0.7%/50%) 3 > 3 340 (1.2%/9%) 405 (0.7%/13%) 58 (0.3%/56%) 166 (0.1%/56%) 668 (0.3%/30%) 4 > 4 219 (0.8%/5%) 250 (0.5%/9%) 24 (0.1%/42%) 71 (0.1%/55%) 359 (0.2%/24%) Number (fraction/false positive rate $^{b}$) of variable objects: Photometry Group 3 Total ... 6677 12741 7567 19214 39522 2 > 2 496 (7.4%/6%) 584 (4.6%/7%) 86 (1.1%/58%) 105 (0.5%/44%) 775 (2.0%/19%) 3 > 3 310 (4.6%/3%) 349 (2.7%/4%) 44 (0.6%/48%) 35 (0.2%/44%) 428 (1.1%/12%) 4 > 4 204 (3.1%/2%) 224 (1.8%/3%) 21 (0.3%/33%) 15 (0.1%/30%) 260 (0.7%/9%) Note. — Photometry Groups 1 and 2 are defined in Section 3; only 49% and 86% of objects in these groups have all four IRAC band measurements, respectively. The remaining objects lack either [5.8], [8.0], or both measurements, so we are unable to place them on the mid-IR color-color diagram (i.e., we were unable to tell if they fall into the modified/old AGN wedge or stellar box). By definition, Photometry Groups 3 includes only objects with all four IRAC measurements. a Column “Outside” includes objects with all four IRAC band measurements only that are both outside of the “Modified AGN Wedge” and the “Stellar Box.” Column “All Objects” contains all objects, regardless of the number of IRAC band measurements. b The fraction of variable sources is a ratio of the number of variable objects above a given level of σ$_{12}$ and r > 0 . 8 to the total number of objects in a respective region. The false positive rate is estimated from the number of sources above the same level of σ$_{12}$ but with r < 0 . 5 (see Section 3 and Figure 3). – 34 –