TITLE: GCN CIRCULAR NUMBER: 23751 SUBJECT: GRB 190114C: RATIR Optical and NIR Detections DATE: 19/01/17 18:07:47 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM Alan M. Watson (UNAM), Nat Butler (ASU), 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), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report: We observed the field of GRB 190114C (Gropp et al., GCN Circ. 23688) 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 2019/01 17.09 to 2019/01 17.29 UTC (53.26 to 58.02 hours after the BAT trigger), obtaining a total of 0.88 hours of exposure in the g and r bands, 1.76 hours exposure i band, and 1.01 hours exposure in the Z, Y, J, and H bands. We detect a source coincident with the enhanced XRT position (Osborne et al., GCN Circ. 23704) and possible host galaxy (de Ugarte Postigo et al., GCN Circ. 23692) with the following magnitudes: r = 20.24 +/- 0.10 i = 19.65 +/- 0.06 Z = 19.48 +/- 0.05 Y = 19.22 +/- 0.03 J = 18.60 +/- 0.04 H = 18.23 +/- 0.06 These magnitudes are in the AB system, in comparison with the USNO-B1 and 2MASS catalogs, and are not corrected for Galactic extinction in the direction of the GRB. The source is still considerably brighter in riz than the Pan-STARRs photometry reported by de Ugarte Postigo et al. (GCN Circ. 23692). Further observations are planned. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.