{
  "bibcode": "2014GCN.16388....1E",
  "body": "P. A. Evans (U Leicester) reports on behalf of the Swift-XRT team:\n\nWe have analysed 11 ks of XRT data for GRB 140610A (Evans  et al. GCN\nCirc. 16375),  from 3.1 ks to 115.0 ks after the  BAT trigger. The data\ncomprise 586 s in Windowed Timing (WT) mode with the remainder in\nPhoton Counting (PC) mode. Using 463 s of PC mode data and 1 UVOT\nimage, we find an enhanced XRT position (using the XRT-UVOT alignment\nand matching UVOT field sources to the USNO-B1 catalogue): RA, Dec =\n286.26899, +3.90822 which is equivalent to:\n\nRA (J2000): 19h 05m 04.56s\nDec(J2000): +03d 54' 29.6\"\n\nwith an uncertainty of 3.1 arcsec (radius, 90% confidence).\n\nThe light curve from T0+3.1-10.6 ks can be modelled with  a power-law\ndecay with a decay index of alpha=0.66 (+0.26, -0.25). At T0+10.6 ks\nthe count rate is 0.04 +/- 0.01 ct/sec. In subsequent observations,\nspanning T0+61-115 ks and containing 7.5 ks of exposure, the source is\nundetected with a 3-sigma upper limit of 0.002 ct/sec. This is\nsubstantially below the extrapolated decay detailed above, and suggests\na decay index of alpha > 1.71.\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 2.3 (+0.9, -0.8). The\nbest-fitting absorption column is 3.1 (+2.0, -1.4) x 10^22 cm^-2, in\nexcess of the Galactic value of 1.2 x 10^22 cm^-2 (Willingale et al.\n2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion\nfactor deduced from this spectrum  is 6.0 x 10^-11 (2.0 x 10^-10) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     3.1 (+2.0, -1.4) x 10^22 cm^-2\nGalactic foreground: 1.2 x 10^22 cm^-2\nExcess significance: 2.2 sigma\nPhoton index:\t     2.3 (+0.9, -0.8)\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00601259.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 16388,
  "createdOn": 1402561981000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 140610A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 140610A"
}