{
  "bibcode": "2021GCN.31081....1M",
  "body": "P. Minaev (IKI), A. Pozanenko (IKI), S. Grebenev (IKI), I. Chelovekov \n(IKI) report on behalf of GRB IKI FuN\n\nWe analyzed GRB 211023A (Di Lalla et al. GCN 30961; Lesage et al. GCN \n30965; Ursi et al. GCN 30969; Ridnaia et al. GCN 31022) using publicly \navailable data of GBM/Fermi and SPI-ACS/INTEGRAL.\n\nUsing GBM/Fermi we clearly detect early emission, starting about 80 s \nbefore the GBM trigger. The extended emission (possibly associated with \nthe activity detected by LAT, Di Lalla et al. GCN 30961, and/or its \nextremely bright afterglow, Zhirkov et al. GCN 30977; Kann et al. GCN \n30982) was also found, becoming dominant since approximately 150 s the \ntrigger. Thus, a time profile consists of three episodes with a total \nburst duration of more than 300 s in GBM/Fermi (7 - 850 keV), while T90 \n= 117 +/- 0.5 s. GRB 211023A was also registered by SPI-ACS/INTEGRAL \nwith marginal detection of the early and the extended emission (T90 = \n120 +/- 9 s). Time profiles of GBM and SPI-ACS are presented at \nhttp://grb.rssi.ru/GRB211023A/GRB211023A_GBM_ACS_light_curve.png\n\nWe performed spectral analysis of the burst using GBM/Fermi data in the \ntime interval of (-20, 160) s after the GBM trigger, covering the main \npart of GRB activity. The best parameters of Band model are following: \nEp = 96 +/- 5 keV, alpha = -1.67 +/- 0.03, beta = -2.21 +/- 0.05 and \nfluence F = (1.341 +/- 0.004)*10^-4 erg/cm^2 in 10 - 1000 keV range. \nAssuming a redshift z = 0.390 (Pozanenko et al., GCN 31053) we estimated \nEiso = (7.45 +/- 0.05)*10^52 erg in the 1 keV - 10 MeV energy band.\n\nThe position of the burst at Ep,i - Eiso and T90,i - EH diagram [1,2] is \nshown by black annuli at\nhttp://grb.rssi.ru/GRB211023A/GRB211023A_Ep-Eiso_two_episodes_SN.png\nand\nhttp://grb.rssi.ru/GRB211023A/GRB211023A_EHD_two_episoses_SN.png\n\nThe position is typical for type II (long) GRBs, although it is in the \nlower bound of their 2 sigma correlation region. This is because of its \nrelatively low value of the Ep,i parameter. Note that low values of Ep,i \nare typical for the nearby bursts (z < 0.5), associated with supernovae \n(shown by red annuli at\nhttp://grb.rssi.ru/GRB211023A/GRB211023A_Ep-Eiso_two_episodes_SN.png\nand\nhttp://grb.rssi.ru/GRB211023A/GRB211023A_EHD_two_episoses_SN.png )\n\n[1] - Minaev et al., MNRAS, 492, 1919, 2020\n[2] - Minaev et al., Astronomy Letters, 46, 9, 573, 2020",
  "circularId": 31081,
  "createdOn": 1636832604000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 211023A: classification and SPI-ACS/INTEGRAL registration",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 211023A"
}