{
  "bibcode": "2018GCN.22652....1T",
  "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 GRB 180418A (D'Elia, et al., GCN 22646) 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 2018/04 18.28 to 2018/04 18.43 UTC\n(1.8 minutes to 3.64 hours after the BAT trigger), obtaining a total of\n2.57 hours exposure in the r and i bands.\n\nAt the position of the optical afterglow (Zheng & Filippenko, GCN 22647),\nin comparison with the SDSS DR9 catalog, we obtain the following\ndetection:\n\n �� r������ = 19.95 +/- 0.01\n\nThis magnitude is in the AB system and is not corrected for Galactic\nextinction in the direction of the GRB.\n\nWe thank the staff of the Observatorio Astron��mico Nacional in San Pedro\nM��rtir.\n\nFurther observations are planned.",
  "circularId": 22652,
  "createdOn": 1524055553000,
  "email": "eleonora.troja@nasa.gov",
  "subject": "GRB 180418A: RATIR Optical Observations",
  "submitter": "Eleonora Troja at GSFC  <eleonora.troja@nasa.gov>",
  "eventId": "GRB 180418A"
}