{
  "bibcode": "2014GCN.16767....1D",
  "body": "M. De Pasquale, A. Maselli (IASF-Palermo), J. R. Cummings (NASA/UMBC)\nreports on behalf of the Swift-XRT team:\n\nWe have analysed 2.9 ks of XRT data for GRB 140903A (Cummings  et al.\nGCN Circ. 16763),  from 74 s to 7.3 ks after the  BAT trigger. The data\nare entirely in Photon Counting (PC) mode. Using 3407 s of PC mode data\nand 7 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 = 238.01361, +27.60259 which is equivalent to:\n\nRA (J2000): 15h 52m 03.27s\nDec(J2000): +27d 36' 09.3\"\n\nwith an uncertainty of 1.7 arcsec (radius, 90% confidence).\n\nThe light curve can be modelled with  a power-law decay with a decay\nindex of alpha=0.21 (+/-0.08).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 1.71 (+0.21, -0.20). The\nbest-fitting absorption column is  1.2 (+0.7, -0.6) x 10^21 cm^-2, in\nexcess of the Galactic value of 3.3 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 4.0 x 10^-11 (4.7 x 10^-11) erg\ncm^-2 count^-1.\n\nA summary of the PC-mode spectrum is thus:\nTotal column:         1.2 (+0.7, -0.6) x 10^21 cm^-2\nGalactic foreground: 3.3 x 10^20 cm^-2\nExcess significance: 2.5 sigma\nPhoton index:         1.71 (+0.21, -0.20)\n\nIf the light curve continues to decay with a power-law decay index of\n0.21, the count rate at T+24 hours will be 0.11 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.5 x\n10^-12 (5.3 x 10^-12) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00611599.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 16767,
  "createdOn": 1409777863000,
  "email": "ucasmd0@ucl.ac.uk",
  "subject": "GRB 140903A: Swift-XRT refined Analysis",
  "submitter": "Massimiliano de Pasquale at IASF-Palermo  <ucasmd0@ucl.ac.uk>",
  "eventId": "GRB 140903A"
}