GCN Circular 30929

M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB),
N. J. Klingler (GSFC/UMBC/CRESSTII), A. Y. Lien (U Tampa),
A. Melandri (INAF-OAB), K. L. Page (U Leicester), D. M. Palmer (LANL)
and T. Sbarrato (INAF-OAB) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 10:42:36 UT, the Swift Burst Alert Telescope (BAT) triggered on 
an event with marginal significance (trigger=1078701). Swift slewed 
immediately to the location. 
The BAT on-board calculated location is 
RA, Dec 287.080, +29.822 which is 
   RA(J2000) = 19h 08m 19s
   Dec(J2000) = +29d 49' 19"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve doesn't show anything
significant. 

The XRT began observing the field at 10:44:08.6 UT, 92.8 seconds after
the BAT trigger. No source was detected in 127 s of promptly downlinked
data. We are waiting for the full dataset to detect and localise the
XRT counterpart. 

UVOT took a finding chart exposure of 138 seconds with the White filter
starting 97 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of
the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
BAT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.231. 

Due to the marginal detection significance in both BAT rates and
on-board  image (6.48 and 6.50 sigma respectively) with no detection
in the ground  image analysis, and the lack of detection by XRT,  we
believe that this is probably a noise fluctuation in BAT and  not an
astrophysical event.