{
  "bibcode": "2009GCN..9222....1F",
  "body": "A. Fernandez-Soto (IFCA-Santander), F. Mannucci (INAF-OAA), D. Fugazza \n(INAF-OAB), L.A. Antonelli (INAF-OAR), S. Campana (INAF-OAB), G. \nChincarini (Univ. Bicocca), S. Covino (INAF-OAB), P. D'Avanzo \n(INAF-OAB/U. Bicocca), V. D'Elia (INAF-OAR), M. Della Valle \n(INAF-OACa/ESO), A. Fiorenzano (TNG), C. Guidorzi (Univ. Ferrara), E. \nMaiorano (IASF-Bo), J. Mao (INAF-OAB), R.  Margutti (INAF-OAB/Univ. \nBicocca), S. Marinoni (TNG), E. Palazzi (IASF-Bo), C. C. Thoene (INAF-OAB)\nreport, on behalf of a larger collaboration (CIBO):\n\nWe have performed an in-depth analysis of the TNG spectrum of GRB090423 \ntaken on Apr 23 at 22:16 UT with the NICS/Amici combination (Thoene et \nal, GCN 9216). We have corrected the wavelength calibration, now based \nboth on the observation of sky features and a fit to the instrument \nsensitivity.\n\nWe detect in the spectrum flux at wavelengths lambda>1.1 microns, and a \nflux compatible with zero below that limit. Interpreting this wavelength \nas the onset of Lyman alpha absorption in the IGM, this leads us to \ndeduce a value of z~8.1.\n\nWe have also analysed all the available photometry (GCNs 9200, 9201, \n9202, 9206, 9209, 9210, 9213, 9214, 9215, 9217, 9218 and 9220) and find \nthat the data are well fit by an afterglow without intrinsic dust \nobscuration, a photometric redshift 7.6<z<8.5, and a temporal decay \nindex 0.50.\n\n[GCN OPS NOTE(24apr09): Per author's request, Marinoni was added\nto the author list.]",
  "circularId": 9222,
  "createdOn": 1240582589000,
  "email": "guidorzi@fe.infn.it",
  "subject": "GRB 090423: Refined TNG analysis",
  "submitter": "Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>",
  "eventId": "GRB 090423"
}