{
  "submittedHow": "email-legacy",
  "circularId": 34497,
  "body": "A. S. Moskvitin, D. V. Oparin (SAO RAS), A. S. Pozanenko (IKI),\nreport on behalf of the larger GRB follow-up collaboration.\n\nWe observed the GRB 230818A OT (Lipunov et al., GCNs 34476, 34477,\n34481, 34482; Gompertz et al., GCN 34480; Moskvitin et al., GCN 34483,\n34495; Malesani et al., GCN 34485; Siegel and Tohuvavohu, GCN 34486;\nPankov et al., GCN 34487; Quadri and Strabla, GCN 34488;\nKlose et al., GCN 34491) with the BTA 6-meter telescope of SAO RAS\nequipped with Scorpio-II. The observations were started since ~ 0.5 h\nafter the burst (Fermi: GBM team, GCN 34478; Swift: Tohuvavohu et al.,\nGCN 34479; AstroSat: Pari et  al., GCN 34492).\n\nIn the 4 x 600 sec spectrum of (4200--8530 AA, FWHM resolution ~ 7A)\nwe identified the absorption lines (C IV, Si II) at a common redshift\nof z = 2.42.  We also identified Si IV and Al II lines at a common\nredshift of 2.38 which might be an intervening system. Thus we confirm\nthe redshift measurement obtained by Malezani et al. (GCN 34485).\n\nUsing acquisition observation we obtained preliminary photometry\nof the afterglow as following (calibrated against Pan-STARRS nearby\nstars)\n\nDate        UT-start   Exptime   Filter  t-T0      OT        Err\n                       sec               days\n2023-08-19  00:00:28   2 x 20     r'     0.02339   19.50 +/- 0.02\n\n",
  "createdOn": 1692478379456,
  "subject": "GRB 230818A: SAO RAS 6-m telescope spectroscopy",
  "bibcode": "2023GCN.34497....1M",
  "submitter": "Moskvitin Alexander at SAO RAS <mosk@sao.ru>",
  "eventId": "GRB 230818A"
}