{
  "bibcode": "2011GCN.11997....1D",
  "body": "P. D'Avanzo (INAF/OAB), V. D'Elia (ASI/ASDC), L. Di Fabrizio, A. Gurtu\n(INAF/TNG), report on behalf of a larger collaboration:\n\nWe observed the optical afterglow of GRB 110503A (Stamatikos et al. GCN\n11991) with the Italian TNG located in La Palma, equipped with the DOLORES\ncamera in spectroscopic mode.\nThe optical afterglow (Leloudas et al. GCN 11994; Kann et al. GCN 11996)\nis clearly detected in the unfiltered acquisition image, with a magnitude\nR~19.5 at at t-t0=4.85 hours (using the calibration of Kann et al. GCN\n11996).\n\nA low-resolution spectrum was taken at a mean time t-t0=5.25 hours. The\nadopted grism was LR-B, covering the wavelength range 3900-8200 AA with a\nresolution of R~600.\nUsing a preliminary wavelength calibration we clearly detect several\nabsorption features, including CIV, SiII, AlIII, AlII, MgII and MgI, all\nat a common redshift z=1.61, in agreement with the value reported by de\nUgarte Postigo et al. (GCN 11993).\nAt the same redshift we also detect the fine structure line SiII*1533.\nThis absorption feature is likely produced in the GRB host, further\nsupporting the statement that z=1.61 is the afterglow redshift.",
  "circularId": 11997,
  "createdOn": 1304468892000,
  "email": "paolo.davanzo@brera.inaf.it",
  "subject": "GRB 110503A: redshift confirmation from TNG",
  "submitter": "Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>",
  "eventId": "GRB 110503A"
}