{
  "bibcode": "2009GCN.10301....1M",
  "body": "C. B. Markwardt (CRESST/GSFC/UMD), A. P. Beardmore (U Leicester),\nD. N. Burrows (PSU), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC),\nS. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),\nK. L. Page (U Leicester), M. H. Siegel (PSU),\nM. Stamatikos (OSU/NASA/GSFC), R. L. C. Starling (U Leicester) and\nT. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:\n\nAt 17:44:17 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated a possible source (trigger=381591).  Swift slewed immediately \nto the source position.  The BAT on-board calculated location is \nRA, Dec 235.079, -8.738 which is \n   RA(J2000) = 15h 40m 19s\n   Dec(J2000) = -08d 44' 15\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed several peaks over\nthe interval T-450 to T+150 sec in the low energy band (15-25 keV).  The\nlater peak was during the slew to the source, so it may not be real.  \nThe peak count rate was ~600 counts/sec (15-350 keV), at ~100 sec after \nthe trigger. \n\nThe XRT began observing the field at 17:46:26.3 UT, 128.9 seconds after\nthe BAT trigger.   The observation lasted only a few minutes before we \nslewed away due to an Earth limb constraint.  No source was detected in \nthe promptly available XRT data.  We are waiting for the full dataset \nfollowing the next ground pass to detect and localise any XRT counterpart. \n\nUVOT took a finding chart exposure of 150 seconds with the White   \nfilter starting 132 seconds after the BAT trigger. UVOT took a second \nfinding chart exposure of 181 seconds with the u filter starting 290 \nseconds after the BAT trigger. No credible afterglow candidate has  \nbeen found in the initial data products. The 2.7'x2.7' sub-images \ncover 25% of the BAT error circle. The typical 3-sigma upper limit \nhas been about 19.6 mag in White and 19.2 in u.  The 8'x8' region for\nthe list of sources generated on-board covers 100% of the BAT error\ncircle. The list of sources is typically complete to about 18.0\nmag. No correction has been made for the expected extinction\ncorresponding to E(B-V) of 0.14. \n\nThe next ground pass is at 1956 UT.  Ground analysis of data from that\npass will be required to determine the nature of this source. \n\nBurst Advocate for this burst is C. B. Markwardt (Craig.Markwardt AT nasa.gov). \nPlease contact the BA by email if you require additional information\nregarding Swift followup of this burst. In extremely urgent cases, after\ntrying the Burst Advocate, you can contact the Swift PI by phone (see\nSwift TOO web site for information: http://www.swift.psu.edu/too.html.)",
  "circularId": 10301,
  "createdOn": 1262283266000,
  "email": "dxb15@psu.edu",
  "subject": "Trigger 381591: Swift detection of a possible burst",
  "submitter": "David Burrows at PSU/Swift  <dxb15@psu.edu>"
}