{
  "createdOn": 1400423099000,
  "subject": "GRB 140518A: RATIR Optical and NIR Observations",
  "editedBy": "Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>",
  "body": "A. Cucchiara (NASA/GSFC), Nat Butler (ASU), Alan M. Watson (UNAM), \nAlexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), \nChris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), \nEleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), \nJosé A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), \nCarlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:\n\nWe observed the field of GRB 140518A (Melandri, et al., GCN 16298) with the\nReionization and Transients Infrared Camera (RATIR; www.ratir.org) on the\n1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on\nSierra San Pedro Mártir from 2014/05 18.41 to 2014/05 18.46 UTC (0.60\nto 1.75 hours after the BAT trigger), obtaining a total of 0.71 hours\nexposure in the r and i bands and 0.30 hours exposure in the Z,\nY, J, and H bands.\n\nWe detect the fading source identified by Zheng et al. (GCN 16299) and \nPerley et al. (GCN 16300) within the Swift-XRT error circle.\nWe confirm this to be the optical afterglow of GRB 140518A.\n\nIn comparison with the SDSS DR9 and 2MASS, we\nobtain the following detections:\n\n  r 20.50 +/- 0.04\n  i 19.00 +/- 0.02\n  Z 18.59 +/- 0.03\n  Y 18.19 +/- 0.03\n  J 18.13 +/- 0.02\n  H 17.80 +/- 0.02\n\nThese magnitudes are in the AB system and are not corrected for Galactic\nextinction in the direction of the GRB.\nBased on these observations, and using our automatic photo-z\nanalysis tool (Littlejohns et al. arXiv:1312.3967) we determine two possible\nphotometric redshifts: assuming a Milky Way extinction curve for the GRB \nhost we derive a photo-z of z=1.88 (+- 0.06) and A_V=1.8, while a SMC \nextinction law gives a z=4.63 (+- 0.11) and A_V=0.5. \nThe second solution is consistent with the spectroscopic redshift\nreported by Chornock et al. (GCN 16301).\n\n\nWe thank the staff of the Observatorio Astronómico Nacional in San Pedro \nMártir.\n\n[GCN OPS NOTE(19may14):  Per author's request, the \"9.90 to 11.05\"\nwas changed to \"0.60 to 1.75\".]",
  "circularId": 16302,
  "bibcode": "2014GCN.16302....1C",
  "submitter": "Antonino Cucchiara at NASA/GSFC  <antonino.cucchiara@nasa.gov>",
  "format": "text/plain",
  "eventId": "GRB 140518A",
  "email": "antonino.cucchiara@nasa.gov",
  "version": 2,
  "editedOn": 1731009485335
}