{
  "bibcode": "2020GCN.28717....1K",
  "body": "D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, \nDARK/NBI), M. Blazek, J. F. Agui Fernandez, C. C. Thoene (all \nHETH/IAA-CSIC), G. Lombardi (GRANTECAN, IAC) and A. Tejero (GRANTECAN) \nreport:\n\nWe observed the afterglow (Ambrosi et al., GCN#28696; Adachi et al., \nGCN#28697; Fu et al., GCN#28701; Belkin et al., GCN#28703; Pankov et \nal., GCN#28708; Kumar et al., GCN#28711; Paek et al., GCN#28713) of GRB \n201020A (Ambrosi et al., GCN#28696; Sakamoto et al., GCN#28705; Bissaldi \net al., GCN#28706) with the 10.4m GTC telescope, at Roque de los \nMuchachos Observatory (La Palma, Spain) equipped with OSIRIS. The \nobservation started on 20 October 2020 at 20:08 UT (14.34 hrs after the \nGRB onset) and consisted of 4 x 900s with the R1000B grism, covering the \nwavelength range between 3700 and 7800 AA. Observations were taken under \ninclement conditions, with bad seeing and thick clouds passing through.\n\nThe spectrum shows a clear continuum, consistent with the Lyman forest, \nLy-alpha, SiII, OI, CII, SiIV, CIV, FeII, FeII*, and AlII, all at a \ncommon redshift of z = 2.903, which we identify as the redshift of the \nGRB.",
  "circularId": 28717,
  "createdOn": 1603276241000,
  "email": "kann@iaa.es",
  "subject": "GRB 201020A: Redshift from GTC/OSIRIS",
  "submitter": "Alexander Kann at IAA-CSIC  <kann@iaa.es>",
  "eventId": "GRB 201020A"
}