{
  "bibcode": "2013GCN.14838....1P",
  "body": "K.L. Page (U. Leicester), C. Pagani (U. Leicester), V. Mangano\n(INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU),\nM.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), A.P. Beardmore\n(U. Leicester) and H.A. Krimm report on behalf of the Swift-XRT team:\n\nWe have analysed 9.4 ks of XRT data for GRB 130608A (Krimm  et al. GCN\nCirc. 14827),  from 147 s to 47.3 ks after the\tBAT trigger. The data\ncomprise 98 s in Windowed Timing (WT) mode (the first 10 s were taken\nwhile Swift was slewing) with the remainder in Photon Counting (PC)\nmode. The enhanced XRT position for this burst was given by Beardmore\net al. (GCN. Circ 14832).\n\nThe light curve can be modelled with an initial power-law decay with an\nindex of alpha=4.33 (+0.26, -0.23), followed by a break at T+653 s to\nan alpha of 0.40 (+0.11, -0.12).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 3.23 (+0.27, -0.25). The\nbest-fitting absorption column is  1.0 (+0.4, -0.3) x 10^21 cm^-2, in\nexcess of the Galactic value of 6.6 x 10^20 cm^-2 (Kalberla et al.\n2005). The PC mode spectrum has a photon index of 2.40 (+0.36, -0.11)\nand a best-fitting absorption column consistent with the Galactic\nvalue. The counts to observed (unabsorbed) 0.3-10 keV flux conversion\nfactor deduced from this spectrum  is 3.0 x 10^-11 (4.0 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     0 (+4.9, -0) x 10^20 cm^-2\nGalactic foreground: 6.6 x 10^20 cm^-2\nExcess significance: <1.6 sigma\nPhoton index:\t     2.40 (+0.36, -0.11)\n\nIf the light curve continues to decay with a power-law decay index of\n0.40, the count rate at T+24 hours will be 7.3 x 10^-3 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.2 x\n10^-13 (3.0 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/00557771.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 14838,
  "createdOn": 1370798887000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 130608A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 130608A"
}