{
  "bibcode": "2017GCN.20963....1O",
  "body": "J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. Melandri\n(INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D.N. Burrows\n(PSU), A. Cholden-Brown (PSU), S. J. LaPorte (PSU), B. Mingo (U.\nLeicester) and\treport on behalf of the Swift-XRT team: report on\nbehalf of the Swift-XRT team:\n\nWe have analysed 7.3 ks of XRT data for GRB 170330A, from 89 s to 53.1\nks after the  BAT trigger. The data comprise 404 s in Windowed Timing\n(WT) mode (the first 7 s were taken while Swift was slewing) with the\nremainder in Photon Counting (PC) mode. \n\nThe light curve can be modelled with an initial power-law decay with an\nindex of alpha=0.71 (+0.07, -0.06), followed by a break at T+439 s to\nan alpha of 1.061 (+0.029, -0.025).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 2.00 (+/-0.10). The\nbest-fitting absorption column is  4.0 (+0.6, -0.5) x 10^21 cm^-2, in\nexcess of the Galactic value of 3.0 x 10^21 cm^-2 (Willingale et al.\n2013). The PC mode spectrum has a photon index of 1.88 (+0.12, -0.11)\nand a best-fitting absorption column of 4.0 (+/-0.6) x 10^21 cm^-2. The\ncounts to observed (unabsorbed) 0.3-10 keV flux conversion factor\ndeduced from this spectrum  is 4.2 x 10^-11 (6.1 x 10^-11) erg cm^-2\ncount^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     4.0 (+/-0.6) x 10^21 cm^-2\nGalactic foreground: 3.0 x 10^21 cm^-2\nExcess significance: 2.6 sigma\nPhoton index:\t     1.88 (+0.12, -0.11)\n\nIf the light curve continues to decay with a power-law decay index of\n1.061, the count rate at T+24 hours will be 0.021 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.7 x\n10^-13 (1.3 x 10^-12) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00744773.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 20963,
  "createdOn": 1490986313000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 170330A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 170330A"
}