{
  "bibcode": "2012GCN.13190....1B",
  "body": "S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester),\nV. D'Elia (ASDC), S. T. Holland (STScI), J. A. Kennea (PSU),\nN. P. M. Kuin (UCL-MSSL), O. M. Littlejohns (U Leicester),\nV. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC),\nC. J. Mountford (U Leicester), K. L. Page (U Leicester),\nT. Sakamoto (NASA/UMBC), R. L. C. Starling (U Leicester) and\nC. A. Swenson (PSU) report on behalf of the Swift Team:\n\nAt 22:49:22 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 120402A (trigger=519207).  Swift slewed immediately to the location. \nThe BAT on-board calculated location is \nRA, Dec 314.326, +19.258, which is \n   RA(J2000)  =  20h 57m 18s\n   Dec(J2000) = +19d 15' 28\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows a single pulse\nwith a duration of about 5 sec.  The peak count rate\nwas ~1300 counts/sec (15-350 keV), at ~1 sec after the trigger. \n\nThe XRT began observing the field at 22:51:08.6 UT, 105.8 seconds after\nthe BAT trigger. No source was detected in 451 s of promptly downlinked\ndata. We are waiting for the full dataset to detect and localise the\nXRT counterpart. \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 109 seconds after the BAT trigger. No credible afterglow candidate has\nbeen found in the initial data products. The 2.7'x2.7' sub-image covers 25% of\nthe BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. \nThe 8'x8' region for the list of sources generated on-board covers 100% of the\nBAT error circle. The list of sources is typically complete to about 18 mag. No\ncorrection has been made for the expected extinction corresponding to E(B-V) of\n0.12. \n\nGiven that the BAT image significance is only 6.6 sigma\nand that the XRT and UVOT do not detect anything, it is \nunlikely that this is a real GRB.  It is possible that\nthis is a noisy detector in the BAT array.  We will have \nto wait for the full data set to downlink to resolve\nthis uncertainty.",
  "circularId": 13190,
  "createdOn": 1333408220000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 120402A: Swift detection of a possible burst or noise",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 120402A"
}