{
  "subject": "GRB050528, XRT observations",
  "eventId": "GRB 050528",
  "bibcode": "2005GCN..3505....1G",
  "createdOn": 1117552243000,
  "circularId": 3505,
  "submitter": "Michael Goad at Leicester U  <mrg@star.le.ac.uk>",
  "email": "mrg@star.le.ac.uk",
  "body": "M. Goad (U. Leicester), J. Kennea (PSU), and D. N. Burrows (PSU) report on\nbehalf of the Swift XRT team:\n \nWe have analysed Swift XRT data from the soft burst GRB050528\n(GCN3496, GCN3502).  The XRT was in an engineering mode at the time of the\nburst and did not begin observations until it was switched back into its\nnormal observing mode.\nAnalysis of 15965 seconds (9 orbits) of Photon Counting mode data starting\n14.15 hours after the BAT trigger reveals 3 faint sources within the BAT 3\narcmin error circle.\n \nThe source coordinates are :\n \nRA(J2000)   23 34 03.7\nDec(J2000) +45 58 18.9\n \nRA(J2000)   23 33 52.1\nDec(J2000) +45 57 40.2\n \nRA(J2000)   23 34 03.2\nDec(J2000) +45 56 03.3\n\nwith an estimated uncertainty of 7 arcsecs radius.\n \nSources 1, 2 and 3 are located 122.1, 146.1 and 14.1 arcsecs from the\nBAT position respectively.\n \nAssuming a Crab like spectrum, photon index 2.1, and column density 1.2e21\ncm-2 the observed count rates correspond to unabsorbed fluxes of 4.9e-14,\n4.2e-14 and 3.2e-14 erg/cm2/s (0.5-10.0 keV), with an uncertainty of\n1.2e-14 erg/cm2/s.\n \nDue to the faintness of the sources, we cannot determine at this time\nwhether any of the sources are fading."
}