TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3998
SUBJECT: Swift trigger 155764: bad XRT centroid
DATE:    05/09/18 19:59:47 GMT
FROM:    David Burrows at PSU/Swift  <dxb15@psu.edu>

D. N. Burrows, J. A. Kennea, and D. Grupe (PSU) report on behalf of the 
Swift XRT team:

The XRT position sent out for Swift trigger 155764 was due to a cosmic ray 
in the XRT field of view, and is not the position of any possible afterglow 
of this event.  This position does not confirm the reality of this 
trigger.  Further analysis is in progress.