{
  "bibcode": "2018GCN.22799....1B",
  "body": "Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC),\nWilliam H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI),\nJ. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara\n(UVI), Eleonora Troja (GSFC), 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 GRB 180620A (Evans, et al., GCN 22798) with the\nReionization and Transients Infrared Camera (RATIR; www.ratir.org) on the\n1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional on\nSierra San Pedro M��rtir from 2018/06 20.36 to 2018/06 20.38 UTC (0.03\nto 0.47 hours after the BAT trigger), obtaining a total of 0.36 hours\nexposure in the r and i bands.\n\nFor a source within the Swift-XRT error circle, in comparison with the\nUSNO-B1 and 2MASS catalogs, we\nobtain the following detections:\n\n  r\t= 18.01 +/- 0.01\n  i\t= 17.71 +/- 0.01\n\nThese magnitudes are in the AB system and are not corrected for Galactic\nextinction in the direction of the GRB.  We observe the rise and\ninitial decline of the afterglow.\n\nWe thank the staff of the Observatorio Astron��mico Nacional in San Pedro\nM��rtir.  Further observations are planned.",
  "circularId": 22799,
  "createdOn": 1529486188000,
  "email": "natbutler@asu.edu",
  "subject": "GRB 180620A: RATIR Optical Afterglow Detection",
  "submitter": "Nat Butler at Az State U  <natbutler@asu.edu>",
  "eventId": "GRB 180620A"
}