{
  "bibcode": "2014GCN.16216....1P",
  "body": "K.L. Page, P.A. Evans and B.P. Gompertz (U Leicester) report on behalf\nof the Swift-XRT team:\n\nWe have analysed 7.7 ks of XRT data for GRB 140506A (Gompertz  et al.\nGCN Circ. 16214),  from 87 s to 30.4 ks after the  BAT trigger. The\ndata comprise 531 s in Windowed Timing (WT) mode (the first 9 s were\ntaken while Swift was slewing) with the remainder in Photon Counting\n(PC) mode. The enhanced XRT position for this burst was given by\nOsborne et al. (GCN Circ. 16215).\n\nThe late-time light curve (from T0+5.1 ks) can be modelled with  a\npower-law decay with a decay index of alpha=0.91 (+/-0.08).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 2.65 (+/-0.03). The\nbest-fitting absorption column is  3.14 (+/-0.10) x 10^21 cm^-2, in\nexcess of the Galactic value of 1.1 x 10^21 cm^-2 (Willingale et al.\n2013). The PC mode spectrum has a photon index of 1.79 (+/-0.09) and a\nbest-fitting absorption column of 2.9 (+/-0.4) 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 (5.6 x 10^-11) erg cm^-2\ncount^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     2.9 (+/-0.4) x 10^21 cm^-2\nGalactic foreground: 1.1 x 10^21 cm^-2\nExcess significance: 7.6 sigma\nPhoton index:\t     1.79 (+/-0.09)\n\nIf the light curve continues to decay with a power-law decay index of\n0.91, the count rate at T+24 hours will be 0.058 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.4 x\n10^-12 (3.2 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/00598284.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 16216,
  "createdOn": 1399455293000,
  "email": "kpa@star.le.ac.uk",
  "subject": "GRB 140506A: Swift-XRT refined Analysis",
  "submitter": "Kim Page at U.of Leicester  <kpa@star.le.ac.uk>",
  "eventId": "GRB 140506A"
}