{
  "createdOn": 1790275246224,
  "body": "S. Dichiara (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P.\nBeardmore (U. Leicester), C. Salvaggio (INAF-OAB), M. Ferro (INAF-OAB),\nR. Brivio (INAF-OAB), D.N. Burrows (PSU) and P.A. Evans report on\nbehalf of the Swift-XRT team:\n\nWe have analysed 6.4 ks of XRT data for GRB 260924A, from 99 s to 43.5\nks after the   trigger. The data comprise 365 s in Windowed Timing (WT)\nmode (the first 10 s were taken while Swift was slewing) with the\nremainder in Photon Counting (PC) mode. \n\nThe late-time light curve (from T0+3.6 ks) can be modelled with an\ninitial power-law decay with an index of alpha=0.89 (+0.08, -0.07),\nfollowed by a break at T+25.9 ks to an alpha of 2.4 (+/-0.7).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 1.491 (+0.017, -0.015). The\nbest-fitting absorption column is  consistent with the Galactic value\nof 4.1 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has\na photon index of 2.03 (+/-0.09) and a best-fitting absorption column\nof 6.9 (+2.2, -2.0) x 10^20 cm^-2. The counts to observed (unabsorbed)\n0.3-10 keV flux conversion factor deduced from this spectrum  is 3.3 x\n10^-11 (3.9 x 10^-11) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     6.9 (+2.2, -2.0) x 10^20 cm^-2\nGalactic foreground: 4.1 x 10^20 cm^-2\nExcess significance: 2.3 sigma\nPhoton index:\t     2.03 (+/-0.09)\n\nIf the light curve continues to decay with a power-law decay index of\n2.4, the count rate at T+24 hours will be 0.050 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.6 x\n10^-12 (1.9 x 10^-12) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttps://www.swift.ac.uk/xrt_products/01513082.\n\nThis circular is an official product of the Swift-XRT team.\n",
  "submittedHow": "email",
  "circularId": 45730,
  "eventId": "GRB 260924A",
  "subject": "GRB 260924A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>"
}