TITLE: GCN CIRCULAR NUMBER: 16170 SUBJECT: GRB 140423A: RATIR Optical and NIR Observations DATE: 14/04/24 17:13:50 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 140423A (Sonbas, et al., GCN 16142) 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 24.29 to 2014/04 24.49 UTC (22.48 to 27.13 hours after the BAT trigger), obtaining a total of 2.56 hours exposure in the r and i bands and 1.07 hours exposure in the Z, Y, J, and H bands. We detect the previously reported optical counterpart candidate (Elenin, et al., GCN 16143; Chester, et al., GCN 16147; Chester, et al., GCN 16157). For a source within the UVOT error circle (Chester, et al., GCN 16147), in comparison with the SDSS DR9 and 2MASS, we obtain the following detections: r 21.90 +/- 0.08 i 21.79 +/- 0.07 Z 21.65 +/- 0.19 Y 21.39 +/- 0.17 J 20.98 +/- 0.20 H 21.33 +/- 0.26 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.