{
  "bibcode": "2012GCN.14120....1F",
  "body": "J. P. U. Fynbo (DARK/NBI), N. R.  Tanvir (U. Leicester), V. D'Elia\n(ASDC, INAF), A. de Ugarte Postigo (IAA-CSIC and DARK/NBI),\nD. Malesani (DARK), O. E. Hartoog (Uva, NL), D. Xu (DARK), H. Flores\n(Obs. Paris), A. J. Levan (U. Warwick), B. Milvang-Jensen (DARK/NBI)\n\nWe observed the field of GRB 121229A (Sonbas et al., GCN 14115; Varela\net al., GCN 14117) with the ESO VLT equipped with the X-shooter\nspectrograph. Observations started at 07:00 UT on 2012-12-29 (2 hr\nafter the BAT trigger), for a total exposure time of ~30 min in each\nof the UVB, VIS, and NIR arms, covering the wavelength range\n3000-21000A.\n\nThe spectrum exhibits two relatively broad troughs (centered at ~ 3800\nand 4500 A) which we interpreted as Lyman-beta and -alpha features,\nrespectively, at z=2.707. We measured the HI column density,\nlogN(HI)~21.7, from the Lyman-alpha feature. At this redshift there\nare tentative indications of other metal absorption features, although\nthey are weak and we have yet to establish their significance. The\nlack of strong resonance metal lines, together with the low X-ray\nabsorption (Sonbas et al., GCN 14115), suggests a low metallicity. We\nalso report a tentative evidence for an intervening MgII absorber at\nz=1.658\n\nWe acknowledge the excellent support of the ESO observing staff, in\nparticular Maja Vu?kovi?.\n\n\n----------------------------------------------------------------\nThis message was sent using IMP, the Internet Messaging Program.",
  "circularId": 14120,
  "createdOn": 1356791882000,
  "email": "delia@asdc.asi.it",
  "subject": "GRB 121229A: VLT/X-shooter redshift",
  "submitter": "Valerio D'Elia at ASDC  <delia@asdc.asi.it>",
  "eventId": "GRB 121229A"
}