{
  "bibcode": "2005GCN..4043....1B",
  "body": "A.P. Beardmore (U. Leicester), K.L. Page (U. Leicester), N. Gehrels (GSFC),\nJ. Greiner (MPE), J. Kennea (PSU),  J. Nousek (PSU), J.P. Osborne (U.\nLeicester) and G. Tagliaferri (INAF-OAB) report on behalf of the Swift/XRT\nteam:\n\nWe have analysed 27.8 ks of XRT data for the BAT soft short burst (trigger\n156838; GCN 4034, Holland et al.), starting 99.5 s after the BAT trigger.\nNo fading X-ray source is found within the refined BAT error circle (GCN\n4037, Markwardt et al.). However, there exists a source with a constant\ncount rate of 0.0015+/-0.0004 counts s^-1 at RA(2000) = 20 13 48.0,\nDec(J2000) = +34 19 53.7 (6.4 arcsec radius uncertainty at 90%\ncontainment) within the BAT error circle, coincident with a B=13.0, R=11.6\nmagnitude USNO object (GSC0267902398 in the Guide Star Catalogue).\n\nThe spectrum of this source is best modelled by either a blackbody (with a\ntemperature of 0.19 +0.10/-0.05 keV, column density < 0.3E22 cm^-2 and an\nunabsorbed 0.2-10.0 keV flux of 7.0E-14 ergs cm^-2 s^-1) or a thermal\nplasma Mekal model (with a temperature of 0.87 +0.41/-0.44 keV, column\ndensity < 0.2E22 cm^-2, an abundance consistent with solar and an\nunabsorbed 0.2-10.0 keV flux of 4.6E-14 ergs cm^-2 s^-1).  We note the\nobserved column density upper limit to this source is significantly less\nthan the Galactic value of 1.1E22 cm^-22 (Dickey & Lockman, 1990),\nsuggesting it is nearby and unlikely to be a GRB.\n\nExcept for the XRT source coincident with the USNO object, there are\nno sources detected within the BAT error circle.  The 3 sigma upper\nlimit on the count-rate is 0.0006 counts s^-1, corresponding to an\nunabsorbed 0.2-10 keV flux of 3.0E-14 ergs cm^-2 s^-1 assuming a\nCrab-like spectrum.",
  "circularId": 4043,
  "createdOn": 1127803720000,
  "email": "kpa@star.le.ac.uk",
  "subject": "GRB050925: Swift/XRT limits",
  "submitter": "Kim Page at U.of Leicester  <kpa@star.le.ac.uk>",
  "eventId": "GRB 050925"
}