TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3172
SUBJECT: Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
DATE:    05/04/02 15:45:36 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <Scott@lheamail.gsfc.nasa.gov>

S. Barthelmy, L. Barbier (GSFC), J. Cummings (GSFC/NRC),
E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS),
M. Suzuki (Saitama), J. Tueller (GSFC)
on behalf of the Swift-BAT team:

At 06:09:55 2-April-2005, UT Swift-BAT triggered on a marginal event
(trigger=113225) which has been reported as GRB 050402 (GCNs 3167, 3168,
3169, 3170).  The BAT team believes that the automated notice sent out earlier
is likely consistent with a noise fluctuation, but we can not absolutely
rule out that it was due to a very soft, weak GRB.  The reasons which make
this a questionable detection are: (a) detected only in the 15-25 keV band,
(b) the image significance is very marginal, and (c) the noise in the
detector array is slightly elevated during this interval (thus increasing
the chance coincidence of a rate fluctuation and an image-domain fluctuation).