{
  "bibcode": "2009GCN..9761....1M",
  "body": "D. Malesani, J.P.U. Fynbo (DARK/NBI), L. Christensen (ESO),\nA. de Ugarte Postigo (OAB-INAF), B. Milvang-Jensen (DARK/NBI),\nS. Covino (OAB-INAF) report on behalf of a larger collaboration\n\nWe have observed the afterglow of GRB 090809 (Markwardt\net al. GCNC 9754) using the X-shooter spectrograph mounted\nat the Kueyen telescope of ESO's VLT (Paranal Observatory,\nChile) during its science verification phase. The spectrum,\nconsisting of a combined exposure of 4x1800s, was started\nat 03:40 UT on August 09 (10.15 hrs after the burst). It was\nobtained with an initial seeing of 0.9\" and an airmass of\n1.2, when the afterglow had a magnitude of R~21. The\nspectrum covers the complete range from 3000 to 25000\nAngstroms. In a preliminary analysis we identify the\nLyman break, Lyman-alpha, SiII, OI, SiI*, SiIV, CIV, FeII, AlII,\nAlIII and MgII at a common redshift of 2.737 +/- 0.002 (pending\nfinal wavelength calibration), which we identify as the redshift\nof the GRB.\n\nWe thank the Paranal staff for excellent support, in particular\nElena Mason and Claudia Cid.",
  "circularId": 9761,
  "createdOn": 1249919688000,
  "email": "deugarte@iaa.es",
  "subject": "GRB 090809 X-shooter redshift",
  "submitter": "Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>",
  "eventId": "GRB 090809"
}