TITLE: GCN CIRCULAR NUMBER: 7117 SUBJECT: GRB 071117: VLT observations and probable redshift DATE: 07/11/19 16:51:43 GMT FROM: Daniele Malesani at Niels Bohr Inst,Dark Cosmology Center P. Jakobsson (Univ. Hertfordshire), J.P.U. Fynbo, D. Malesani (DARK/NBI), N.R. Tanvir (Univ. Leicester), B. Milvang-Jensen (DARK/NBI), A.O. Jaunsen (Univ. Oslo), P.M. Vreeswijk, J. Hjorth (DARK/NBI), report on behalf of a larger collaboration: We observed the field of GRB 071117 (Ukwatta et al., GCN 7098) with the ESO VLT, starting on 2007 Nov 18.005 UT (9.28 hr after the GRB). We clearly detect the two sources indicated by Bloom (GCNs 7105, 7110), including the afterglow s2. Source s1 appears extended in our images, while source s2 is indeed pointlike (seeing 0.85"). A faint nebulosity is apparent surrounding both objects. A VLT spectrum was obtained with the FORS1 instrument starting on 2007 Nov 18.03 UT, placing both sources on the slit. Three exposures of 30 min each were secured. The afterglow spectrum shows a faint, blue continuum between 3700 to 9000 A, and a weak emission line is apparent at 8688 A. Interpreting this as [OII], we infer a redshift of z=1.331, which we consider as the likely redshift of the GRB. Interpreting the observed line as [OIII] or Halpha, we would expect to detect [OII] at 6466 or 4934 A, respectively, which we do not see. A more conservative upper limit to the GRB redshift comes from the nondetection of any dropout in the blue down to 3800 A, which implies z < 2.1. The spectrum of s1 is very red, with no significant flux below 5000 A. A plot of the 2D spectrum and a finding chart showing the afterglow and the various XRT error circles is posted at: https://grbtoo.dark-cosmology.dk/public/gcn-pages/grb-071117/ We acknowledge excellent support from the ESO observing staff, in particular Stephane Brillant and Emanuela Pompei.