{
  "bibcode": "2013GCN.14812....1B",
  "body": "D.N. Burrows (PSU), B.P. Gompertz (U. Leicester), J.P. Osborne (U.\nLeicester), K.L. Page (U. Leicester), V. D'Elia (ASDC), A. Maselli \n(INAF-IASFPA), V. Mangano (INAF-IASFPA), J.A. Kennea (PSU), M.C. Stroh\n(PSU) and T.N. Ukwatta report on behalf of the Swift-XRT team:\n\nWe have analysed 7.6 ks of XRT data for GRB 130606A (Ukwatta  et al.\nGCN Circ. 14781),  from 62 s to 58.7 ks after the  BAT trigger. The\ndata comprise 499 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 14811).\n\nThe late-time light curve (from T0+5.3 ks) can be modelled with  a\npower-law decay with a decay index of alpha=1.13 (+0.10, -0.09).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 1.55 (+/-0.04). The\nbest-fitting absorption column is  8.4 (+/-1.0) x 10^20 cm^-2, in\nexcess of the Galactic value of 2.0 x 10^20 cm^-2 (Kalberla et al.\n2005). The PC mode spectrum has a photon index of 1.84 (+0.15, -0.14)\nand a best-fitting absorption column of 4.5 (+3.1, -2.5) x 10^20 cm^-2.\nThe counts to observed (unabsorbed) 0.3-10 keV flux conversion factor\ndeduced from this spectrum  is 3.8 x 10^-11 (4.2 x 10^-11) erg cm^-2\ncount^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     4.5 (+3.1, -2.5) x 10^20 cm^-2\nGalactic foreground: 2.0 x 10^20 cm^-2\nExcess significance: <1.6 sigma\nPhoton index:\t     1.84 (+0.15, -0.14)\n\nIf the light curve continues to decay with a power-law decay index of\n1.13, the count rate at T+24 hours will be 0.011 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.3 x\n10^-13 (4.8 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/00557589.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 14812,
  "createdOn": 1370622363000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 130606A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 130606A"
}