{
  "bibcode": "2024GCN.35456....1B",
  "subject": "GRB 240101A: Swift-XRT refined Analysis",
  "body": "D.N. Burrows (PSU), J. D. Gropp (PSU), A.P. Beardmore (U. Leicester),\nJ.P. Osborne (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri\n(INAF-OAR), T. Sbarrato (INAF-OAB), S. Dichiara (PSU) and P.A. Evans\nreport on behalf of the Swift-XRT team:\n\nWe have analysed 6.8 ks of XRT data for GRB 240101A, from 142 s to 57.6\nks after the  BAT trigger. The data are entirely in Photon Counting\n(PC) mode. \n\nThe light curve can be modelled with a power-law decay with a decay\nindex of alpha=1.06 (+0.08, -0.07).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 2.1 (+/-0.3). The\nbest-fitting absorption column is  4.3 (+1.8, -1.5) x 10^21 cm^-2, in\nexcess of the Galactic value of 5.8 x 10^20 cm^-2 (Willingale et al.\n2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion\nfactor deduced from this spectrum  is 3.9 x 10^-11 (6.5 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     4.3 (+1.8, -1.5) x 10^21 cm^-2\nGalactic foreground: 5.8 x 10^20 cm^-2\nExcess significance: 4.1 sigma\nPhoton index:\t     2.1 (+/-0.3)\n\nIf the light curve continues to decay with a power-law decay index of\n1.06, the count rate at T+24 hours will be 1.4 x 10^-3 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.6 x\n10^-14 (9.3 x 10^-14) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/01205708.\n\nThis circular is an official product of the Swift-XRT team.\n",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "eventId": "GRB 240101A",
  "circularId": 35456,
  "createdOn": 1704193911074,
  "submittedHow": "email"
}