TITLE: GCN CIRCULAR NUMBER: 20149 SUBJECT: GRB 161108A: RATIR Afterglow Confirmation DATE: 16/11/08 14:29:23 GMT FROM: Nat Butler at Az State U Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report: We observed the field of GRB 161108A (Beardmore, et al., GCN 20145) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2016/11 8.48 to 2016/11 8.54 UTC (7.87 to 9.34 hours after the BAT trigger), obtaining a total of 1.03 hours exposure in the r and i bands and 0.40 hours exposure in the Z, Y, J, and H bands. The afterglow candidate reported by Malesani et al. (GCN 20146) is well detected. In comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following detections and upper limits (3-sigma): r = 21.97 +/- 0.12 i = 21.36 +/- 0.06 Z = 20.88 +/- 0.11 Y = 20.57 +/- 0.14 J = 20.05 +/- 0.27 H > 18.12 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. The source appears to have faded in r by about 1 magnitude as compared to Malesani et al. (GCN 20146). We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.