{
  "bibcode": "2011GCN.12154....1K",
  "body": "H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC),V. D'Elia (ASDC),\nC. B. Markwardt (NASA/GSFC), D. M. Palmer (LANL),  G. Stratta (ASDC)\n\nBased on a non-detection in the XRT and a low significance in the BAT,\nwe conclude thatSwift/BAT trigger 457076 (Krimm et al, GCN 12149) was\nmost likely caused by a chance fluctuation in the BAT image domain\nand is not due to a burst or other astrophysical phenomenon.\n\nXRT began observing the field of the Swift trigger 457076 (Krimm et al.,\nGCN circ 12149) 167 s after the burst trigger. We analyzed the first\n2.6 ks of XRT data, from 167 s until 10 ks after the trigger. No\ncandidate afterglow is detected in the BAT error circle, and the\nthree sigma upper limit for any new source in the field of view is\n4.3e-3 counts/second.\n\nWe examined the BAT event data from T-60 to T+243, when a slew took\nthe trigger position out of the field of view. The significance of\nthe event is reduced in ground processing to 5.5 sigma.  The light\ncurve shows a positive excess in the two lowest energy bands as\nwould be expected from an image trigger, but the increase is only\nduring the trigger interval, and the two bands are only weakly\ncorrelated with each other.  There is no indication of earlier\nor later emission.  This result, combined with the null result\nfrom the XRT, leads us to our conclusion.",
  "circularId": 12154,
  "createdOn": 1310473564000,
  "email": "hans.a.krimm@nasa.gov",
  "subject": "Swift trigger 457076 is not a GRB",
  "submitter": "Hans Krimm at NASA-GSFC  <hans.a.krimm@nasa.gov>"
}