{
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "body": "S. Dichiara (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P.\nBeardmore (U. Leicester), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti\n(INAF-OAB), C. Salvaggio (INAF-OAB), D.N. Burrows (PSU) and P.A. Evans\nreport on behalf of the Swift-XRT team:\n\nWe have analysed 8.6 ks of XRT data for GRB 250114A, from 117 s to 28.1\nks after the  BAT trigger. The data comprise 317 s in Windowed Timing\n(WT) mode (the first 9 s were taken while Swift was slewing) with the\nremainder in Photon Counting (PC) mode. \n\nThe late-time light curve (from T0+4.6 ks) can be modelled with an\ninitial rise, with a power-law index of alpha=-0.94 (+1.18, -0.25),\nfollowed by a break at T+8035 s  to an alpha of 1.32 (+0.31, -0.29).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 1.09 (+/-0.03). The\nbest-fitting absorption column is  1.8 (+/-0.9) x 10^22 cm^-2, at a\nredshift of 4.732, in addition to the Galactic value of 5.1 x 10^20\ncm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index\nof 1.87 (+0.14, -0.13) and a best-fitting absorption column of 1.0\n(+2.2, -1.0) x 10^22 cm^-2. The counts to observed (unabsorbed) 0.3-10\nkeV flux conversion factor deduced from this spectrum  is 3.6 x 10^-11\n(4.1 x 10^-11) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nGalactic foreground: 5.1 x 10^20 cm^-2\nIntrinsic column:    1.0 (+2.2, -1.0) x 10^22 cm^-2 at z=4.732\nPhoton index:\t     1.87 (+0.14, -0.13)\n\nIf the light curve continues to decay with a power-law decay index of\n1.32, the count rate at T+24 hours will be 6.8 x 10^-3 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.4 x\n10^-13 (2.8 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/01281241.\n\nThis circular is an official product of the Swift-XRT team.\n",
  "eventId": "GRB 250114A",
  "circularId": 38945,
  "bibcode": "2025GCN.38945....1D",
  "subject": "GRB 250114A: Swift-XRT refined Analysis",
  "submittedHow": "email",
  "createdOn": 1736883704974
}