{
  "bibcode": "2013GCN.14225....1M",
  "body": "Daniele Malesani, Thomas Kruehler (DARK/NBI), Daniel Perley (Caltech), \nJohan P. U. Fynbo, Dong Xu, Bo Milvang-Jensen (DARK/NBI), Paolo Goldoni \n(APC, CEA/Irfu), Steve Schulze (PUC and MCSS), report on behalf of the \nX-shooter GTO GRB collaboration:\n\nWe observed the field of GRB 120118B (Littlejohns et al., GCN 12852) \nwith the Keck I telescope located on Mauna Kea. Observations were \ncarried out on 2013 Feb 10 (389 days after the GRB), using the LRIS \ninstrument, simultaneously in the g and I bands, for a total exposure \ntime of 750 and 720 s, respectively. Consistent with the latest XRT \nposition (Osborne et al. GCN 12857; see also \nhttp://www.swift.ac.uk/xrt_positions/), we detect a bright, slightly \nextended object (I = 23.8, Vega), which we consider to be the GRB host \ngalaxy. Its coordinates are (J2000):\n\nRA = 08:19:29.047\nDec = -07:11:05.14\n\nThis position is consistent with that of the tentative near-infrared \ncounterpart reported by D'Avanzo & Palazzi (GCN 12870).\n\nA spectrum of this source was taken on 2013 Feb 13 with the ESO VLT \nequipped with the X-shooter spectrograph, covering the wavelength range \n3000-20500 AA. The seeing was 0.6\". In the NIR arm, we detect several \nemission lines, interpreted as [O III] (5007), [Ne III] (3869), and \nhints for [O III] (4959) and [O II] (3727) at a common redshift z = \n2.943. The weakness/lack of other prominent lines usually seen in GRB \nhost spectra is readily explained by their location in non-favorable \nparts of the spectrum. In the UVB arm, the host continuum is detected \ndown to ~4750 AA, which corresponds to the onset of the Lyman alpha \nforest at z = 2.943.\n\nAt z = 2.94 the host is a fairly luminous galaxy at 2000 � rest-frame, \nroughly 0.5 mag brighter than L* at that redshift (e.g. Gabasch et al. \n2004, A&A, 421, 41). The properties of this object are akin to those of \nLyman-break galaxies.\n\nWe acknowledge excellent support from the observing staff at Mauna Kea \nand Paranal, in particular Cedric Ledoux and Andrea Mehner.",
  "circularId": 14225,
  "createdOn": 1361065612000,
  "email": "malesani@dark-cosmology.dk",
  "subject": "GRB 120118B: host observations and redshift determination",
  "submitter": "Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>",
  "eventId": "GRB 120118B"
}