{
  "bibcode": "2021GCN.31342....1D",
  "body": "V. D'Elia (SSDC & INAF-OAR), S. R. Oates (U.Birmingham), A. D'Ai\n(INAF-IASFPA), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), D.N.\nBurrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester),\nA. Melandri (INAF-OAB) and P.A. Evans (U. Leicester) report on behalf\nof the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the\nSwift/BAT-GUANO-detected burst GRB 211229A (Tohuvavohu et al., GCN\nCirc. 31334), also detected by Fermi/GBM and GECAM  (Fermi GBM team,\nGCN Circ. 31329, Zhao et al., GCN Circ. 31331), collecting 5.0 ks of\nPhoton Counting (PC) mode data between T0+43.6 ks and T0+66.8 ks. \n\nFour uncatalogued X-ray sources have been detected consistent with\nbeing within 394 arcsec of the Swift/BAT-GUANO position, however none\nof them is above the RASS limit or shows definitive signs of fading.\nTherefore, at the present time we cannot identify which, if any, is the\nafterglow. Details of these sources are given below:\n\nSource 1:\n  RA (J2000.0):  295.1317  =  19:40:31.60\n  Dec (J2000.0): +23.1983  =  +23:11:53.8\n  Error: 6.3 arcsec (radius, 90% conf.)\n  Count-rate: (3.5 [+1.3, -1.0])e-3 ct s^-1   \n  Distance: 252 arcsec from Swift/BAT-GUANO position.\n  Flux: (2.78 [+1.01, -0.83])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\n\nSource 2:\n  RA (J2000.0):  295.0615  =  19:40:14.76\n  Dec (J2000.0): +23.2617  =  +23:15:42.0\n  Error: 9.7 arcsec (radius, 90% conf.)\n  Count-rate: (1.60 [+0.88, -0.66])e-3 ct s^-1\t \n  Distance: 398 arcsec from Swift/BAT-GUANO position.\n\nSource 5:\n  RA (J2000.0):  295.0738  =  19:40:17.70\n  Dec (J2000.0): +23.1573  =  +23:09:26.3\n  Error: 6.6 arcsec (radius, 90% conf.)\n  Count-rate: (2.12 [+0.97, -0.76])e-3 ct s^-1\t \n  Distance: 20 arcsec from Swift/BAT-GUANO position.\n  Flux: (1.59 [+0.72, -0.57])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)\n\n\nSource 6:\n  RA (J2000.0):  295.1187  =  19:40:28.49\n  Dec (J2000.0): +23.1638  =  +23:09:49.7\n  Error: 5.3 arcsec (radius, 90% conf.)\n  Count-rate: (2.94 [+1.13, -0.91])e-3 ct s^-1\t \n  Distance: 151 arcsec from Swift/BAT-GUANO position.\n\nAn uncatalogued source was also detected, however this was too far from\nthe GRB position to be the afterglow.\n\nThe results of the XRT-team automatic analysis of the XRT observations,\nincluding a position-specific upper limit calculator, are available at\nhttps://www.swift.ac.uk/ToO_GRBs/00021475.\n\nNo optical afterglow consistent with the GUANO position\n(Tohuvavohu et al., GCN Circ. 31334)\nis detected in the initial UVOT exposures.\n\nPreliminary 3-sigma upper limits using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial\nexposures are:\n\nFilter\t       T_start(s)   T_stop(s)\t   Exp(s)\t  Mag\n\nu\t\t 43722\t      66830\t      4882\t   >21.0\n\nThe magnitudes in the table are not corrected for the Galactic\nextinction\ndue to the reddening of E(B-V) = 5.811 in the direction of the burst\n(Schlegel et al. 1998).\n\nThis circular is an official product of the Swift-XRT and UVOT team.",
  "circularId": 31342,
  "createdOn": 1640885346000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 211229A: Swift-XRT and UVOT observations",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 211229A"
}