{
  "bibcode": "2013GCN.14555....1M",
  "body": "A. Melandri (INAF-OAB) and S. Immler (NASA/CRESST/GSFC) report on  \nbehalf of the Swift-XRT team:\n\nWe have analysed  8.3 ks of XRT data for the Fermi/LAT-detected burst:  \nGRB 130502B (Kocevski  et al. GCN Circ. 14532), from 55.1 ks to 101.8  \nks after the Fermi/LAT trigger.\n\nThe object dectected in the first 3.4 ks of XRT data (Melandri &  \nImmler GCN Circ. 14540) is now clearly fading. The light curve can be  \nmodelled with  a power-law decay with a decay index of alpha=1.52  \n(+/-0.25).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed  \npower-law with a photon spectral index of 1.89 (+/-0.20). The best- \nfitting absorption column is  1.73 (+0.78, -0.71) x 10^21 cm^-2, in  \naddition to the Galactic value of 1.1 x 10^21 cm^-2 (Kalberla et al.  \n2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion  \nfactor deduced from this spectrum  is 4.3 x 10^-11 (6.3 x 10^-11) erg  \ncm^-2 count^-1.\n\nA summary of the PC-mode spectrum is thus:\nGalactic foreground:    1.1 x 10^21 cm^-2\nIntrinsic column:         1.73 (+0.78, -0.71) x 10^20 cm^-2\nPhoton index:\t         1.89 (+0.21, -0.20)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00020266.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 14555,
  "createdOn": 1367674251000,
  "email": "andrea.melandri@brera.inaf.it",
  "subject": "GRB 130502B: Swift-XRT refined Analysis",
  "submitter": "Andrea Melandri at INAF-OAB  <andrea.melandri@brera.inaf.it>",
  "eventId": "GRB 130502B"
}