[vsnet-grb-info 9848] Refined analysis shows Swift Trigger 435520 is not a GRB

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  11316
SUBJECT: Refined analysis shows Swift Trigger 435520 is not a GRB
DATE:    10/10/03 22:14:53 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

S. Barthelmy (GSFC), J. Kennea (PSU), and R. Margutti (INAF-OAB)
report on behalf of the Swift team:

Using the full data set (T-64 to T+240 sec) from the recent downlink,
refined ground analysis shows that the Swift-BAT trigger 435520
(Cummings, et al., Circ 11315) is due to a chance fluctuation
in the image domain.  It is not a GRB, nor anything astrophysical.

Swift-XRT obtained 1.5 ks of Photon Counting (PC) mode data, from T0+160 s
to T0+1.7 ks.  No source is found in the BAT error circle, with a 3-sigma
upper limit of 6.7 x 10-3  ct/sec; for a typical GRB, this would correspond
to an upper limit on the observed 0.3-10 keV flux of 3.4 x 10-13 erg cm-2 s-1.