{
  "bibcode": "2015GCN.17672....1P",
  "body": "V. Pugliese (API/Uva), D. Xu (DARK/NBI), N. R. Tanvir, K. Wiersema (U.\nLeicester), J. P. U. Fynbo, B. Milvang-Jensen (DARK/NBI), V. D'Elia\n(ASI/ASDC and INAF/Roma) report on behalf of a larger collaboration:\n\nWe observed the afterglow of GRB 150403A (Lien et al. GCN 17665; Longo\net al. GCN 17667) with X-shooter at the Very Large Telescope (Paranal\nObservatory, Chile). Observations started at 08:44:48 UT on 2015-04-04\n(i.e., 10.84 hr after the burst), and consisted of photometry in V-,\nr-, z-, and g- bands as well as spectroscopy of 4x600 s exposures\ncovering the spectral range between 3000 and 25000 AA, equipped with\nUVB/VIS/NIR arms.\n\nThe optical afterglow is well detected in each photometric image, and\nhas m(R) ~ 19.1 mag at 10.85 hr post-burst, calibrated with nearby\nUSNO B1 stars. For the spectroscopy, prominent absorption lines are\ndetected in a continuum throughout the arms. In a preliminary\nreduction we detect absorption features of SII, SiIV, OI, SiII, SiII*,\nCII, CII*, CIV, AlII, NiII*, FeII, FeII*, MnI, MgII, MgI at a common\nredshift of z = 2.06, which is consistent with a broad Lya trough at\nthe same redshift. We suggest this is the redshift of the GRB.\n\nWe also detect an intervening system at z=1.76, identified with\nabsorption lines of SiII, CIV, AlII, and so on.\n\nWe acknowledge the excellent support provided by Paranal staff, and in\nparticular Andrea Mehner, and Emanuela Pompei.",
  "circularId": 17672,
  "createdOn": 1428149165000,
  "email": "dong.dark@gmail.com",
  "subject": "GRB 150403A: VLT/X-shooter redshift",
  "submitter": "Dong Xu at DARK/NBI  <dong.dark@gmail.com>",
  "eventId": "GRB 150403A"
}