{
  "bibcode": "2014GCN.16139....1L",
  "body": "Owen Littlejohns (ASU), Nat Butler (ASU), Alan M. Watson (UNAM),\nAlexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer\n(UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC),\nJosh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja\n(GSFC), Enrico Ramirez-Ruiz (UCSC), Jos�� A. de Diego (UNAM), Leonid\nGeorgiev (UNAM), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM),\nNeil Gehrels (GSFC), and Harvey Moseley (GSFC) report:\n\nWe observed the field of GRB 140419A (Marshall, et al., GCN 16118) with\nthe Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on\nthe 1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional\non Sierra San Pedro M��rtir from 2014/04 21.14 to 2014/04 21.29 UTC (47.30\nto 50.93 hours after the BAT trigger), obtaining a total of 2.49 hours\nexposure in the r and i bands and 1.04 hours exposure in the Z, Y, J, and\nH bands.\n\nWe continue to detect the UVOT optical transient (Zheng, et al., GCN 16116;\nGuver et al., GCN 16120). For a source located at the position of the KAIT\noptical counterpart candidate (Zheng, et al., GCN 16119), in comparison with\nthe SDSS DR9 and 2MASS, we obtain the following detections and upper limit\n(3-sigma):\n\n  r     21.92 +/- 0.07\n  i     21.77 +/- 0.07\n  Z     21.74 +/- 0.13\n  Y     21.58 +/- 0.19\n  J     21.54 +/- 0.21\n  H     > 21.66\n\nThese magnitudes are in the AB system and are not corrected for Galactic\nextinction in the direction of the GRB. In comparison to the first two\nepochs of RATIR observations (Littlejohns, et al., GCN 16136; Butler, et\nal., GCN 16121) we note that the decay in the NIR bands appears steeper,\nnow consistent with 1.4 < alpha < 1.6 in the i, Z, Y, J and H bands (see\nalso; Xu et al., GCN 16138). The XRT data for this GRB\n(http://www.swift.ac.uk/xrt_curves/00596426/) may support a temporal break\nat low significance after 100 ks. Further XRTdata can constrain this\npossibility.\n\nConversely, the decay observed in the r band has become shallower, with\nalpha = 0.8. This shallow decay in the r band could be attributed to the\npresence of an underlying host galaxy or contamination from the nearby\nbright star.\n\nWe thank the staff of the Observatorio Astron��mico Nacional in San Pedro\nM��rtir.",
  "circularId": 16139,
  "createdOn": 1398107953000,
  "email": "olittlej@asu.edu",
  "subject": "GRB 140419A: Continued RATIR Optical and NIR Observations",
  "submitter": "Owen Littlejohns at Az State U  <olittlej@asu.edu>",
  "eventId": "GRB 140419A"
}