{
  "submitter": "Alexei Pozanenko at IKI, Moscow <grb.alex@gmail.com>",
  "eventId": "GRB 260310A",
  "createdOn": 1774045906031,
  "body": "A. Volnova (IKI), N. Pankov (IKI), E. Klunko (ISTP), A. S. Moskvitin\n(SAO RAS), O. Spiridonova (SAO RAS), A. Pozanenko (IKI) report on\nbehalf of GRB IKI FuN.\n\nWe observed the field of GRB260310A/AT2026fgk detected by Fermi/GBM\n(Fermi GBM team, GCN 43951) and AstroSat(Salunke et al., GCN 43958)\nwith AZT-33IK telescope of Mondy observatory. We obtained series in B\nand R filters starting on 2026-03-13.\n\nThe OT discovered by GOTO (O'Neill et al. 2026, TNS Discovery Report\n294132) and observed earlier (Konno et al., GCN 43974; Hinds et al.,\nGCN 43977; Lipunov et al., GCN 43978;Martin-Carrillo et al., GCN\n43979; Méndez et al., GCN 43980;de Ugarte Postigo et al., GCN 43984;\nHsu et al., GCN 43986; Pursiainen et al., GCN 43990; Becerra et al.,\nGCN 43991; Li et al., GCN 43993; Jayaraman et al., GCN 43994; Stein et\nal., GCN 43996;Martin-Carrillo et al., GCN 44000; Moreno Méndez et\nal., GCN 43980; Becerra et al., GCN 43991; Li et al., GCN 43993; Stein\net al., GCN 43996; Watson et al., GCN 44001; Lai et al., GCN 44002;\nIzzo et al., GCN 44003; Brivio et al., GCN 44004; Moskvitin et al.,\nGCN 44006; Romanov, GCN 44020; Brosio et al., GCN 44021; Pawar et al.,\nGCN 44022; Belkin et al., GCN 44043; Li et al., GCN 44044; Gupta et\nal., GCN 44051) is clearly detected in our images. Preliminary PSF\nphotometry on some epochs is the following\n\nDate UT_start t_mid - T0, filter exp, mag err UL(3sigma)\ndays s\n2026-03-15 15:09:04 5.43535 15*120 B 19.18 0.05 23.0\n2026-03-16 14:37:32 6.41345 15*120 B 19.05 0.05 22.6\n2026-03-17 18:59:03 7.60549 30*120 B 19.18 0.05 22.7\n2026-03-18 18:40:29 8.58565 19*120 B 19.47 0.06 21.7\n2026-03-19 18:09:48 9.57128 30*120 B 19.61 0.06 23.2\n\n2026-03-15 14:48:55 5.52493 11*120 R 18.27 0.05 23.0\n2026-03-16 14:07:40 6.39202 13*120 R 18.22 0.05 22.8\n2026-03-17 18:22:13 7.56948 15*120 R 18.29 0.06 22.8\n2026-03-18 18:06:29 8.55786 15*120 R 18.60 0.06 22.4\n2026-03-19 19:11:16 9.60355 15*120 R 18.71 0.07 22.7\n\nThe photometry is based on the nearby calibrations stars of PS1\ncatalogue converted to B, R using the Lupton (2005) transformations.\nThe magnitudes are not corrected for Galactic extinctions.\n\nWe do not observe the rebrightening reported in COLIBRÍ observations\n(Becerra et al., GCN 44059) up to the latest epoch (~9.6 days) in B,R\n- filters.\nBased on classification of the progenitor (Atteia et al., GCN 43981;\nMinaev et al., GCN 44053) we urge follow up observations to search for\na supernova associated with GRB 260310A.\n",
  "circularId": 44060,
  "subject": "GRB 260310A: no evidence of re-brightening up to 9.6 days in optical observation at Mondy",
  "submittedHow": "email"
}