{
  "bibcode": "2022GCN.32769....1B",
  "body": "S. Belkin (IKI, HSE), V. Kim (FAI), A. Pozanenko (IKI),  M. Krugov \n(FAI), Y. Aimuratov (FAI), N. Pankov (HSE) report on behalf of GRB IKI FuN:\n\nWe continue observations of GRB 221009A (Swift J1913.1+1946) (Dichiara \net al., GCN 32632; Kennea and Williams, GCN  32635; Veres et al., GCN \n32636; Bissaldi et al., GCN  32636; Svinkin et al., GCN 32641; Piano et \nal., GCN 32657; Pillera et al., GCN 32658;  Gotz et al., GCN 32660; \nFrederiks et al., GCN 32668)  with AZT-20 telescope of Assy-Turgen \nobservatory.  The observations were carried out  on 2022-10-11 -- \n2022-10-15. The optical afterglow ( GCNs 32632,  32635, 32636, 32641, \n32657, 32658, 32660, 32666, 32668, 32670, 32671, 32676, 32677, 32678, \n32679, 32680, 32683, 32684, 32685, 32686, 32691, 32692, 32693, 32694, \n32695, 32700, 32705, 32707, 32709, 32727, 32729, 32730, 32736, 32738, \n32739, 32740, 32743, 32746, 32749, 32750; 32752; 32753; 32755; 32758; \n32765).\n\nPreliminary photometry of the afterglow on 2022-10-15 is following\n\nDate       UT start  t-T0       Exp.   Filter  OT    Err.   UL(3sigma)\n                     (mid, days)  (s)\n2022-10-15 15:29:43  6,10259    30*60  g'      22.60  0.12  23.4\n2022-10-15 14:25:00  6,05765    30*60  r'      20.96  0.05  22.9\n2022-10-15 14:56:19  6,07939    30*60  i'      20.00  0.04  23.2 \n2022-10-15 16:01:07  6,11918    15*60  z'      19.31  0.08  21.0\nThe photometry is based on the nearby PS1 stars.\n\nThe light curve based in our photometry can be found in \nhttp://grb.rssi.ru/GRB221009A/GRB221009A_lc_cc_7_cut.png\n\nThe power law (PL) fit parameters are also shown in the figure and do \nnot include photometry on 2022-10-15. It can be seen that the color \nchange g-i and photometry g, r on October 15, 2022 deviate significantly \nfrom the PL approximation. We hypothesize that this behaviour may \nindicate a supernova rise.",
  "circularId": 32769,
  "createdOn": 1665934409000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 221009A: continued Assy optical afterglow observations, possible SN evidence",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 221009A"
}