{
  "bibcode": "2021GCN.30583....1K",
  "body": "D.A. Kann (HETH/IAA-CSIC), L. Izzo (DARK/NBI), A.J. Levan (Radboud),  D.B. Malesani (DTU Space), S. de Wet (UCT) report for the STARGATE collaboration: \n\n\"We observed the afterglow of GRB 210731A (Troja et al. GCN 30568, de Wet et al. GCN 30570) with the ESO VLT UT3 equipped with the X-shooter spectrograph on 1 Aug 2021. A total of 4800 s (4x1200 s) of spectra were obtained starting at 02:45 UT (approximately 28.5 hours after the burst). \n\nThe afterglow is well detected in the acquisition imaging with r=20.7+/- 0.1, and a continuum is visible across the X-shooter spectral range. The spectra contain several prominent absorption features of Fe II, Al III, Mg II and Mg I, at a common redshift z=1.2525. This is consistent with the detection of the afterglow in all the UVOT filters (Kuin & Troja GCN 30572), and we suggest it to be the redshift of GRB 210731A. \n\nWe thank the Paranal staff for the excellent assistance in securing these observations.\"",
  "circularId": 30583,
  "createdOn": 1627898004000,
  "email": "a.levan@astro.ru.nl",
  "subject": "GRB 210731A: VLT/X-shooter redshift",
  "submitter": "Andrew Levan at U.of Leicester  <a.levan@astro.ru.nl>",
  "eventId": "GRB 210731A"
}