TITLE: GCN CIRCULAR NUMBER: 16091 SUBJECT: GRB 140408A: RATIR Optical Upper Limits DATE: 14/04/09 23:48:05 GMT FROM: Owen Littlejohns at Az State U Owen Littlejohns (ASU), 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 (ORAU/GSFC), Eleonora Troja (GSFC), 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 140408A (D'Elia, et al., GCN 16082) 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 2014/04 9.41 to 2014/04 9.48 UTC (20.52 to 22.37 hours after the BAT trigger), obtaining a total of 1.42 hours exposure in the r and i bands. For a source within the Swift-XRT error circle we obtain the following upper limits (3-sigma): r > 22.84 i > 22.53 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. These upper limits are consistent with the previously reported GROND afterglow candidate (Varela, et al., GCN 16089). We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.