{
  "bibcode": "2020GCN.28847....1X",
  "body": "D. Xu (NAOC), J.-B. Vielfaure (APC, Paris University), D. A. Kann \n(HETH/IAA-CSIC), D. B. Malesani (DTU Space), D. A. Perley (LJMU), A. J. \nLevan (Radboud U. Nijmegen), S. Klose, B. Stecklum (both TLS Tautenburg),\nK. Wiersema (Univ. Warwick), and A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI) \nreport on behalf of the Stargate Consortium:\n\nWe observed the transient ZTF20acozryr/AT2020yxz (Coughlin et al., GCN \n28841), which has been proposed to be the optical afterglow of GRB \n201103B (Svinkin et al., GCN 28844) using the ESO VLT UT3 (Melipal) \nequipped with the X-shooter spectrograph. Our spectra cover the \nwavelength range 3000-21000 AA, and consist of 4 exposures of 1200 s \neach. The observation mid-time was 2020 Nov 6.116 UT (56.66 hr/2.361 \ndays after the GRB).\n\nIn a 60 s image taken with the acquisition camera on Nov 6.0771 UT, we \ndetect the optical afterglow, for which we measure a preliminary \nmagnitude r ~ 20.7 mag (AB magnitude, calibrated against a nearby galaxy \nfrom the Pan-STARRS catalog; Chambers et al. 2016, arXiv:1612.05560).\n\nWe clearly detect continuum over the entire wavelength range. From \ndetection of multiple absorption features, which we interpret as due to \nCII, MgII, and multiple FeII lines, we infer a redshift z = 1.105. We \nsuggest this to be the redshift of the transient, which we hereby \nconfirm spectroscopically to be the afterglow of GRB 201103B.\n\nWe acknowledge excellent support from the ESO observing staff in Paranal,\nin particular Ivan Aranda and Matias Jones.\n\n[GCN OPS NOTE(04nov2020): Per author's request, Ivan Aranda and Matias Jones\nwere added to the last sentence.]\n[GCN OPS NOTE(07nov20): Per author's request, Stecklum was added\nto the author's list.]",
  "circularId": 28847,
  "createdOn": 1604638718000,
  "email": "dxu@nao.cas.cn",
  "subject": "GRB 201103B (ZTF20acozryr/AT2020yxz): VLT/X-shooter redshift",
  "submitter": "Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>",
  "eventId": "GRB 201103B"
}