{
  "bibcode": "2021GCN.29277....1M",
  "body": "A. S. Moskvitin, V. V. Vlasyuk (SAO RAS)\non behalf of GRB follow-up team report.\n\nWe observed the field of the GRB 210104A (Fermi GBM Team, GCN #29232;\nTroja et al., GCN #29233; Biltzinger et al., GCN #29234)\nwith the 0.5m Astrosib RC500-2 telescope of SAO RAS\nequipped with the Rc filter and FLI Proline PL16801 camera.\nThe observations carried out on 2021 Jan. 4, 0.32--0.38 days\nafter the trigger (T_mid - T0 = 0.35d).\n\n\nIn the 37 x 20 sec. stacked image we clearly detect the GRB OT\n(Troja et al., GCN #29233; Xin et al., GCN #29235; Hu et al.,\nGCN #29236; Hosokawa et al., GCN #29237; Kim et al., GCN #29238;\nLipunov et al., GCN #29239; Horiuchi et al., GCN #29241;\nBreeveld et al., GCN #29247; Zhu et al., GCN #29252; Paek et al.,\nGCN #29254; Kumar et al., GCN #29257; Smartt et al., GCN #29262;\nV. Kim, GCN #29265; S. Anandagoda, GCN #29273; P. Gokuldass,\nGCN #29274; J. Mao, GCN #29275)\nwith the brightness of R = 19.4 +/- 0.1. The preliminary photometry\nis based on R2 magnitudes of nearby USNO-B1 stars.",
  "circularId": 29277,
  "createdOn": 1610031645000,
  "email": "mosk@sao.ru",
  "subject": "GRB 210104A: SAO RAS optical observations",
  "submitter": "Moskvitin Alexander at SAO RAS  <mosk@sao.ru>",
  "eventId": "GRB 210104A"
}