{
  "bibcode": "2005GCN..2974....1P",
  "body": "C. Pagani (OAB), J. Kennea, D. N. Burrows, J. E. Hill, J. A. Nousek (PSU), G.\nChincarini, G. Tagliaferri, A. Moretti, P. Romano, S. Campana (OAB), M. Goad,\nK. Page, A. Wells, J. Osborne, A. Beardmore (U. Leicester), M. Chester (PSU),\nS. Barthelmy, N. Gehrels, N. White (GSFC), P. Schady (MSSL), M. Tripicco\n(GSFC), L. Cominsky (Sonoma State U.),\nP. Giommi (ASDC) on behalf of the Swift XRT team.\n\nThe Swift X-Ray Telescope (XRT) was pointed at GRB050124 ( GCN 2972, Markwardt\net al.; GCN 2973, Cummings et al.) on 2005/01/24 at 14:34 UT.  The spacecraft\ndid not autonomously slew to the burst since automated slewing was not enabled\nat the time the burst occurred.  The observation was performed as a Target of\nOpportunity beginning about 3 hours after the burst.  The first XRT exposure\nwas at 14:35:16 UT.  The observation continued until 15:17:12 UT.  The XRT was\nin Auto State and the ToO was performed as if it were an automated burst\nobservation.  XRT attempted to determine a prompt centroid but found\ninsufficient counts.  It took one frame in Piled-up Photodiode mode, one in\nLow-rate Photodiode mode, and then settled into Windowed Timing mode (1-D\nposition resolution, 2 ms timing) for the bulk of the observation (1100\nframes), with about 220 frames in Photon-Counting mode (2-D position\nresolution, 2.5s timing).\n\nWe processed the data on the ground and detect a bright X-ray source in this\nfield.  The X-ray centroid has an approximate location of:\nRA(J2000) = 12:51:31.1\nDec(J2000) = 13:02:34.3.\n\nThis position is not corrected for stellar aberration, and we estimate an\nuncertainty of about 30 arcseconds as a result.  A more accurate position will\nbe available once the data are processed by the XRT pipeline software.\n\nChecks against SIMBAD and the HEASARC master X-ray catalog yielded no known\nsource at this position on the sky.   The XRT position is about 70 arcseconds\nfrom the refined BAT positions (GCN 2973).\n\nWe have a total of about 600 counts from this object in the first observation\nset.  The spectrum appears consistent with a power-law, but detailed fitting\nawaits the pipeline-processed data.  Additional automated observations are in\nprogress when the afterglow field is observable by Swift.\n\n[GCN OPS NOTE (24Jan05): In the first line, the \"GRB010124\" was changed to \"GRB050124\"\nas per author's request.]",
  "circularId": 2974,
  "createdOn": 1106591841000,
  "email": "burrows@astro.psu.edu",
  "subject": "GRB 050124: Swift XRT Detection of X-ray Afterglow Emission",
  "submitter": "David Burrows at PSU/Swift  <burrows@astro.psu.edu>",
  "eventId": "GRB 050124"
}