{
  "bibcode": "2013GCN.15173....1G",
  "body": "Dirk Grupe (PSU) and Stephen Holland (STSCI) report on behalf of the\nSwift team:\n\nWe have analysed 3.2 ks of XRT data for the INTEGRAL-detected burst:\nGRB 130903A,  from 39.6 ks to 46.4 ks after the  INTEGRAL trigger. The\ndata are entirely in Photon Counting (PC) mode.  An X-ray source is\ndetected within the INTEGRAL error circle (Mereghetti et al., GCN circ.\n15169). Using 1789 s of PC mode data and 1 UVOT images, we find an\nenhanced XRT position (using the XRT-UVOT alignment and matching UVOT\nfield sources to the USNO-B1 catalogue): RA, Dec = 82.13013, -0.12667\nwhich is equivalent to:\n\nRA (J2000): 05h 28m 31.23s\nDec(J2000): -00d 07' 36.0\"\n\nwith an uncertainty of 4.3 arcsec (radius, 90% confidence). This\nposition is 12 arcsec from the INTEGRAL position.  Currently the source\nhas a 0.3-10 keV count rate in the Swift XRT of (4.9+4.9-3.0)e-3\ncounts/s.\nWe cannot determine at the present time whether the source is fading.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00020294.\n\nThe Swift UVOT observed the field of GRB 130903A in V and U for 2462\nand 780s, respectively. No optical counterpart was found. The 3-sigma\nupper limits at the position of the X-ray source are 20.6 in V and 20.4\nin U.\n\n\nThis circular is an official product of the Swift team.",
  "circularId": 15173,
  "createdOn": 1378239077000,
  "email": "dxg35@psu.edu",
  "subject": "GRB 130903A: Swift-XRT observations",
  "submitter": "Dirk Grupe at PSU/Swift-XRT  <dxg35@psu.edu>",
  "eventId": "GRB 130903A"
}