{
  "bibcode": "2018GCN.23496....1W",
  "body": "Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),\nWilliam H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J.\nXavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI),\nEleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz\n(UCSC), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Harvey\nMoseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki\nToy (UMD) report:\n\nWe observed the field of GRB 181202A (Cannizzo et al., GCN 23482) with\nthe Reionization and Transients Infrared Camera (RATIR; www.ratir.org)\non the 1.5m Harold Johnson Telescope at the Observatorio Astron��mico\nNacional on Sierra San Pedro M��rtir from 2018/12 3.09 to 2018/12 3.11\nUTC (19.43 to 20.04 hours after the BAT trigger), obtaining a total of\n0.09 hours exposure in the r and i bands and 0.12 hours exposure in the\nZ, Y, J, and H bands in poor conditions.\n\nFor a source within the Swift-XRT error circle, in comparison with the\nUSNO-B1 and 2MASS catalogs, we obtain the following 3-sigma upper\nlimits:\n\n r\t> 19.18\n i\t> 19.17\n Z\t> 16.52\n Y\t> 16.30\n J\t> 16.00\n H\t> 16.31\n\nThese magnitudes are in the AB system and are not corrected for Galactic\nextinction in the direction of the GRB.\n\nHowever, we note that in our optimally-combined all-filter image, there\nappears to be a very faint source present in the Swift-XRT error circle.\nThis suggests that there may be a source present at low significance in\nat least some of our individual images.\n\nWe thank the staff of the Observatorio Astron��mico Nacional in San Pedro\nM��rtir.",
  "circularId": 23496,
  "createdOn": 1543858062000,
  "email": "alan@astro.unam.mx",
  "subject": "GRB 181202A: RATIR Optical and NIR Observations",
  "submitter": "Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>",
  "eventId": "GRB 181202A"
}