{
  "bibcode": "2009GCN..9250....1W",
  "body": "K. Wiersema (Leicester), A. de Ugarte Postigo (ESO) and A. Levan (Warwick) \nreport on behalf of a larger collaboration:\n\nWe observed the afterglow of GRB 090424 (Cannizzo et al, GCN 9223) with \nthe ISIS spectrograph on the William Herschel Telescope at the \nObservatorio del Roque de los Muchachos on La Palma, ~8 hours after burst.\n\nIn the spectrum we find several lines, among others the Mg II doublet \n(with restframe EW > 1 A of the 2796 line), Fe II, Na I. Through these we \nconfirm the redshift of z=0.544 found by Chornock et al (GCN 9243). \nContinuum is detected up to at least 3200 A, giving an upper limit to the \nGRB redshift of 1.6, consistent with the emission and absorption redshift \nof 0.544.\n\nWe thank the staff of the WHT, in particular O. Vadivescu, for support for \nthese observations.",
  "circularId": 9250,
  "createdOn": 1240680183000,
  "email": "kw113@star.le.ac.uk",
  "subject": "GRB 090424: WHT ISIS spectroscopy",
  "submitter": "Klaas Wiersema at U of Leicester  <kw113@star.le.ac.uk>",
  "eventId": "GRB 090424"
}