TITLE: GCN CIRCULAR NUMBER: 20444 SUBJECT: GRB 170112A: RATIR Optical and NIR Observations DATE: 17/01/12 23:48:48 GMT FROM: Eleonora Troja at GSFC Eleonora Troja (GSFC), 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), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), 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 the short GRB 170112A (Mingo, et al., GCN 20436) 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 2017/01 12.15 to 2017/01 12.21 UTC (1.58 to 2.95 hours after the BAT trigger), obtaining a total of 0.76 hours exposure in the r and i bands and 0.32 hours exposure in the Z and Y bands. Comparison to the DSS reveals no obvious new source brighter than about magnitude 19. However our data are deeper and we cannot yet exclude a fainter counterpart. Further observations to check for variability are planned. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.