{
  "subject": "GRB 071020: BTA spectroscopy",
  "editedOn": 1731924649751,
  "version": 2,
  "eventId": "GRB 071020",
  "bibcode": "2007GCN..6984....1F",
  "createdOn": 1193238041000,
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>",
  "submitter": "Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>",
  "circularId": 6984,
  "email": "ajct@iaa.es",
  "format": "text/plain",
  "body": "T. A. Fatkhullin, V. V. Sokolov (SAO-RAS Nizhnij Arkhyz), S. Guziy \n(Nikolaev St. Univ.), A. de Ugarte Postigo (ESO Santiago), D. \nPérez-Ramírez (Univ. de Jaén and U. Leicester), J. Gorosabel, M. Jelínek \nand A. J. Castro-Tirado (IAA-CSIC Granada), on behalf of a larger \ncollaboration, report:\n\n\"Following the detection of GRB 071020 by SWIFT (Holland et al. GCN \nCirc. 6949)  we obtained optical spectroscopy with the 6.0m BTA \ntelescope (+SCORPIO) of the SAO-RAS.  In spite of poor weather \nconditions (dense cirrus) we managed to get 4 x 1200s spectra of the \nproposed optical afterglow (Schaefer et al. GCN Circ. 6948). The data \nwere taken on Oct 21.05 U.T. (i.e. 18 hr after the event), with the VPHG \n400 grism (range 3700-9000 A).\n\nWe identify absorption lines from Fe II (2344, 2586 and 2600) and \npossibly C IV (1548-1550) and Fe II (1608), at z = 2.142 ± 0.002. This \nconfirms the lower limit to the GRB 071020 redshift derived from VLT \nspectroscopy (Jakobsson et al., GCN Circ.  6952). Moreover, we do not \nsee any flux drop in the OA spectrum around 4300 A as the VLT spectrum \nmay suggest. However, there are indications of a flux drop at ~3870A but\nthe low S/N ratio in this range prevents us to draw any further \nconclusion.\"\n\nThis message can be quoted."
}