{
  "subject": "GRB 180305A: RATIR Optical Afterglow Candidate",
  "eventId": "GRB 180305A",
  "bibcode": "2018GCN.22460....1T",
  "createdOn": 1520335481000,
  "circularId": 22460,
  "submitter": "Eleonora Troja at GSFC  <eleonora.troja@nasa.gov>",
  "email": "eleonora.troja@nasa.gov",
  "body": "Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM),\nAlexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM),\nOri Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB),\nAntonino Cucchiara (UVI), Owen Littlejohns (ASU), Enrico\nRamirez-Ruiz (UCSC), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM),\nHarvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and\nVicki Toy (UMD) report:\n\nWe observed the field of the LAT GRB 180305A (Axelsson, et al., GCN 22457)\nwith the 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 2018/03 6.11 to 2018/03 6.20 UTC\n(17.28 to 19.45 hours after the burst), obtaining a total of 1.36 hours\nexposure in the r and i bands.\n\nAt the position of source #2 found by Swift-XRT�� (Evans, et al., GCN \n22459),\nwe detect a faint uncatalogued optical source. In comparison with the\nUSNO-B1 catalog, we obtain the following detections:\n\n �� r������ = 21.95 +/- 0.12\n �� i������ = 21.48 +/- 0.08\n\nThese magnitudes are in the AB system and are not corrected for Galactic\nextinction in the direction of the GRB.\nThe source is located at RA,Dec = 03:18:28.33,+32:06:36.2 (J2000, +/-0.5\").\n\nFurther observations to establish fading of the optical source are planned.\n\nWe thank the staff of the Observatorio Astron��mico Nacional in San Pedro\nM��rtir."
}