{
  "body": "K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. D'Ai\n(INAF-IASFPA), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), A.\nTohuvavohu (U. Toronto), D.N. Burrows (PSU), J. D. Gropp (PSU) and P.A.\nEvans report on behalf of the Swift-XRT team:\n\nWe have analysed 8.2 ks of XRT data for GRB 240805B, from 71 s to 30.3\nks after the  BAT trigger. The data comprise 4.5 ks in Windowed Timing\n(WT) mode (the first 6 s were taken while Swift was slewing) with the\nremainder in Photon Counting (PC) mode. \n\nThe late-time light curve (from T0+5.6 ks) can be modelled with a\npower-law decay with a decay index of alpha=1.55 (+/-0.26).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 1.77 (+/-0.06). The\nbest-fitting absorption column is  1.19 (+0.21, -0.20) x 10^21 cm^-2,\nin excess of the Galactic value of 7.6 x 10^20 cm^-2 (Willingale et al.\n2013). The PC mode spectrum has a photon index of 1.9 (+0.4, -0.3) and\na best-fitting absorption column of 1.5 (+1.4, -0.7) x 10^21 cm^-2. The\ncounts to observed (unabsorbed) 0.3-10 keV flux conversion factor\ndeduced from this spectrum  is 3.6 x 10^-11 (4.6 x 10^-11) erg cm^-2\ncount^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     1.5 (+1.4, -0.7) x 10^21 cm^-2\nGalactic foreground: 7.6 x 10^20 cm^-2\nExcess significance: <1.6 sigma\nPhoton index:\t     1.9 (+0.4, -0.3)\n\nIf the light curve continues to decay with a power-law decay index of\n1.55, the count rate at T+24 hours will be 3.4 x 10^-3 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x\n10^-13 (1.6 x 10^-13) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/01246989.\n\nThis circular is an official product of the Swift-XRT team.\n",
  "circularId": 37059,
  "bibcode": "2024GCN.37059....1P",
  "eventId": "GRB 240805B",
  "subject": "GRB 240805B: Swift-XRT refined Analysis",
  "createdOn": 1722911231312,
  "submittedHow": "email",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>"
}