{
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "bibcode": "2024GCN.36071....1D",
  "body": "P. D'Avanzo (INAF-OAB), J. D. Gropp (PSU), S. Dichiara (PSU), J.A.\nKennea (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U.\nLeicester), M.G. Bernardini (INAF-OAB), E. Ambrosi  (INAF-IASFPA)  and\nP.A. Evans report on behalf of the Swift-XRT team:\n\nWe have analysed 3.9 ks of XRT data for GRB 240411B, from 160 s to 74.6\nks after the  BAT trigger. The data comprise 10 s in Windowed Timing\n(WT) mode (taken while Swift was slewing), with the remainder in Photon\nCounting (PC) mode. \n\nThe light curve can be modelled with a power-law decay with a decay\nindex of alpha=0.66 (+0.12, -0.11).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 2.13 (+0.38, -0.20). The\nbest-fitting absorption column is  consistent with the Galactic value\nof 1.1 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed\n(unabsorbed) 0.3-10 keV flux conversion factor deduced from this\nspectrum  is 3.2 x 10^-11 (4.1 x 10^-11) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     1.1 (+/-1.0) x 10^21 cm^-2\nGalactic foreground: 1.1 x 10^21 cm^-2\nExcess significance: <1.6 sigma\nPhoton index:\t     2.13 (+0.38, -0.20)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/01221183.\n\nThis circular is an official product of the Swift-XRT team.\n",
  "circularId": 36071,
  "subject": "GRB 240411B: Swift-XRT refined Analysis",
  "submittedHow": "email",
  "eventId": "GRB 240411B",
  "createdOn": 1712939789424
}