{
  "bibcode": "2016GCN.19250....1B",
  "body": "Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William\nH. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier\nProchaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI),\nEleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC),\nJos�� A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes��s Gonz��lez (UNAM),\nCarlos Rom��n-Z����iga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC),\nJohn Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:\n\nWe observed the field of GRB 160327A (Racusin, et al., GCN 19235) for a\nthird epoch with 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 2016/04 1.22 to\n2016/04 1.41 UTC (115.97 to 120.62 hours after the BAT trigger), obtaining\na total of 3.18 hours exposure in the r and i bands and 1.34 hours exposure\nin the Z, Y, J, and H bands.\n\nWe are able to detect two of the three sources identified by the GTC (de\nUgarte Postigo, et al., GCN 19245).  The afterglow (GTC source #1 and\nGolkhou, et al., GCN 19236) is detected in our night 2 observations on 28\nMarch (Golkhou, et al., GCN 19243) but not on 1 April.  The GTC source #2\nis detected on 28 March and 1 April and is the dominant source in terms of\nbrightness.  We do not detect GTC source #3 on either night.\n\nIn comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following\ndetections and upper limits (3-sigma):\n\nAfterglow (GTC Source #1):\n\n 28 March                 1 April\nr > 24.37               r > 24.41\ni = 24.20 +/- 0.31      i > 24.38\nZ = 22.98 +/- 0.28      Z > 23.15\nY > 22.85               Y > 22.91\nJ > 22.67               J > 22.61\nH > 22.21               H > 22.23\n\nGTC Source #2:\n\n 28 March                 1 April\nr = 23.84 +/- 0.22      r > 24.42\ni = 23.33 +/- 0.14      i = 23.57 +/- 0.17\nZ = 22.57 +/- 0.20      Z = 22.71 +/- 0.25\nY = 22.83 +/- 0.35      Y > 22.73\nJ = 22.43 +/- 0.29      J > 22.60\nH = 21.75 +/- 0.24      H > 22.24\n\nGTC Source #3:\n\n 28 March                 1 April\nr > 24.37               r > 24.41\ni > 24.34               i > 24.39\nZ > 23.19               Z > 23.11\nY > 22.86               Y > 22.76\nJ > 22.66               J > 22.6\nH > 22.21               H > 22.25\n\nThese magnitudes are in the AB system and are not corrected for Galactic\nextinction in the direction of the GRB.\n\nIn addition to our first night observations (Golkhou, et al., GCN 19236),\nwhich show the afterglow peaking and then fading, our observations on 28\nMarch and 1 April confirm the fading of the afterglow.  The above\nphotometric analysis, based on PSF fitting, may still suffer from modest\ncontamination between sources.  More detailed analyses are under way.\n\nWe thank the staff of the Observatorio Astron��mico Nacional in San Pedro\nM��rtir.",
  "circularId": 19250,
  "createdOn": 1459538419000,
  "email": "natbutler@asu.edu",
  "subject": "GRB 160327A: Continued RATIR Optical and NIR Observations",
  "submitter": "Nat Butler at Az State U  <natbutler@asu.edu>",
  "eventId": "GRB 160327A"
}