{
  "bibcode": "2021GCN.30281....1J",
  "body": "M. Jelinek, J. Strobl, R. Hudec, C. Polasek (ASU CAS Ondrejov)\nreport:\n\nWe observed the optical afterglow of GRB 210619B (D'Avanzo et al. GCN\n30261; Jelinek et al. GCN 30263; Lipunov et al. GCN 30259; Zhao et al. GCN\n30261; Kong et al. GCN 30265; Axelsson et al. GCN 30270; de Ugarte Postigo\net al. GCN 30272; Zheng et al. GCN 30273; Blazek et al. GCN 30274; Kann et\nal. GCN 30275; Svinkin et al. GCN 30276; Xin et al. GCN 30277; Perley et\nal. GCN 30271, Shrestha et al. GCN 30280) with the D50 in Ondrejov through\ndifficult conditions with some passing clouds.\n\nOn a combined (86x60s, Sloan r') image with the mean exposure time 0.98\ndays post burst we measure r'(AB) = 20.2 +- 0.2. This is significantly\nbelow any extrapolation of photometric points published before, and\nsuggests a break and a steepening of the decay.",
  "circularId": 30281,
  "createdOn": 1624236928000,
  "email": "martin.jelinek@asu.cas.cz",
  "subject": "GRB 210619B: steepening of the decay observed at the D50",
  "submitter": "Martin Jelinek at Astro.Inst-AVCR,Ondrejov  <martin.jelinek@asu.cas.cz>",
  "eventId": "GRB 210619B"
}