TITLE: GCN CIRCULAR NUMBER: 15226 SUBJECT: GRB 130912A: RATIR Optical and NIR Upper Limits DATE: 13/09/13 15:25:38 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), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UCSC), 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), and Harvey Moseley (GSFC) report: We observed the field of GRB 130912A (D'Elia et al., GCN 15212) 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 2013/09 13.30 to 2013/09 13.49 UTC (22.58 to 27.11 hours after the BAT trigger), obtaining a total of 5.33 hours exposure in the r and i bands and 2.24 hours exposure in the Z, Y, J, and H bands. For a source within the Swift-XRT error circle, in comparison with USNO-B1 and 2MASS, we obtain the following upper limits (3-sigma): r > 23.89 i > 23.79 Z > 22.86 Y > 22.38 J > 22.30 H > 21.78 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. Our observations confirm that the source faded and is therefore the short GRB afterglow. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.