{
  "bibcode": "2017GCN.21051....1T",
  "body": "Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM),\nAlexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer\n(UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB),\nAntonino Cucchiara(UVI), 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 (ASU), and Vicki\nToy (UMD) report:\n\nWe observed the field of GRB 170428A (Beardmore, et al., GCN 21042)\nwith the Reionization and Transients Infrared Camera (RATIR;\nwww.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio\nAstron��mico Nacional on Sierra San Pedro M��rtir from 2017/04 29.41 to\n2017/04 29.48 UTC (24.69 to 26.25 hours after the BAT trigger), obtaining\na total of 0.90 hours exposure in the r and i bands and 0.35 hours\nexposure in the Z, Y, J, and H bands.\n\nFor a source at the candidate afterglow position (Bolmer, et al., GCN \n21050),\nin comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following\ndetection and upper limits (3-sigma):\n\n   r    > 22.3\n   i    22.1 +/- 0.4\n   Z    > 20.9\n   Y    > 20.6\n   J    > 20.1\n   H    > 19.9\n\nThese magnitudes are in the AB system and are not corrected for Galactic\nextinction in the direction of the GRB.\n\nOur observations show that the source reported by Bolmer, et al., (GCN \n21050)\nsignificantly faded, and is therefore the afterglow of the short \nGRB170428A.\n\nWe thank the staff of the Observatorio Astron��mico Nacional in San Pedro\nM��rtir.",
  "circularId": 21051,
  "createdOn": 1493491236000,
  "email": "eleonora.troja@nasa.gov",
  "subject": "GRB 170428A: RATIR Afterglow Confirmation",
  "submitter": "Eleonora Troja at GSFC  <eleonora.troja@nasa.gov>",
  "eventId": "GRB 170428A"
}