{
  "bibcode": "2014GCN.16986....1P",
  "body": "C. Pagani, K. L. Page and P. A. Evans (U. Leicester) report on behalf\nof the Swift-XRT team:\n\nWe have analysed 3.0 ks of XRT data for the Fermi/LAT-detected burst:\nGRB 141028A,  from 31.0 ks to 71.7 ks after the Fermi/LAT trigger. The\ndata are entirely in Photon Counting (PC) mode.  An X-ray source is\ndetected within the Fermi/LAT error circle. Using 348 s of PC mode data\nand 1 UVOT images, we find an enhanced XRT position (using the XRT-UVOT\nalignment and matching UVOT field sources to the USNO-B1 catalogue):\nRA, Dec = 322.60168, -0.23145 which is equivalent to:\n\nRA (J2000): 21h 30m 24.40s\nDec(J2000): -00d 13' 53.2\"\n\nwith an uncertainty of 4.0 arcsec (radius, 90% confidence). This\nposition is 367 arcsec from the Fermi/LAT position (Bissaldi et al. GCN\n16969) and consistent with the positions of the optical counterpart\ndetected by MASTER (Gorbovskoy et al. GCN 16972), GROND (Graham et al.\nGCN 16977) and UVOT (Siegel et al. GCN 16979).\n\nThe light curve can be modelled with  a power-law decay with a decay\nindex of alpha=2.0 (+/-1.0).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 2.5 (+/-0.5). The\nbest-fitting absorption column is  1.8 (+2.2, -1.3) x 10^21 cm^-2, in\nexcess of the Galactic value of 4.1 x 10^20 cm^-2 (Willingale et al.\n2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion\nfactor deduced from this spectrum  is 3.0 x 10^-11 (5.0 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     1.8 (+2.2, -1.3) x 10^21 cm^-2\nGalactic foreground: 4.1 x 10^20 cm^-2\nExcess significance: 1.8 sigma\nPhoton index:\t     2.5 (+/-0.5)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00020420.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 16986,
  "createdOn": 1414600773000,
  "email": "cp232@star.le.ac.uk",
  "subject": "GRB 141028A: Swift-XRT observations",
  "submitter": "Claudio Pagani at U of Leicester  <cp232@star.le.ac.uk>",
  "eventId": "GRB 141028A"
}