{
  "bibcode": "2012GCN.13460....1X",
  "body": "D. Xu (WIS), J. P. U. Fynbo (DARK/NBI), V. D'Elia (ASDC, INAF), N. R.\nTanvir (U. Leicester) report on behalf of the X-shooter GRB GTO\ncollaboration:\n\nWe observed the field of GRB 120712A (Page et al., GCN 13454) with the\nESO VLT equipped with the X-shooter spectrograph. Observations started\nat 00:06 UT on 2012-07-13 (10.4 hr after the BAT trigger), for a total\nexposure time of ~60 min in each of the UVB, VIS, and NIR arms,\ncovering the wavelength range 3000-25000A.\n\nThe spectrum exhibits a relatively broad trough (centered at ~6292A)\nwhich we interpreted as Lyman-alpha break. Redward of this feature the\nspectrum shows metals lines such as Mg II, Si II, and  Fe II, all at a\ncommon redshift z=4.1745. We also measured the HI column density,\nlogN(HI)~20.3, from the Lyman-alpha feature.\n\nWe acknowledge the excellent support of the ESO observing staff, in\nparticular Fernando J. Selman.",
  "circularId": 13460,
  "createdOn": 1342148877000,
  "email": "dong.dark@gmail.com",
  "subject": "GRB 120712A: VLT/Xshooter redshift",
  "submitter": "Dong Xu at Weizmann Inst  <dong.dark@gmail.com>",
  "eventId": "GRB 120712A"
}