GCN Circular 5339

M. Stamatikos (NASA/ORAU), S. D. Barthelmy (GSFC), M. Capalbi (ASDC),
J. R. Cummings (NASA/UMD), C. Gronwall (PSU),
C. Guidorzi (Univ Bicocca&INAF-OAB), K. M. McLean (LANL/UTD),
K. L. Page (U Leicester), D. M. Palmer (LANL) and M. Perri (ASDC)
report on behalf of the Swift Team:

At 06:50:36 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 060719 (trigger=220020).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA,Dec 18.456, -48.375 {01h 13m 49s, -48d 22' 30"} (J2000)
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows two peaks, the first
starting at T_zero for ~4 sec and the second starting at T+40 for ~15 sec. 
The peak count rate is 3000 counts/sec (15-350 keV) at ~T+1 sec. 

The XRT began observing the field at 06:51:53 UT, 77 seconds after the
BAT trigger. XRT found a bright, variable, uncatalogued X-ray source
located at RA(J2000) = 01h 13m 43.3s, Dec(J2000) = -48d 22' 53.5", with an
estimated uncertainty of 4.0 arcseconds (90% confidence radius). 
This location is 64 arcseconds from the BAT on-board position, within
the BAT error circle. The initial flux in the 2.5s image was
2.7e-09 erg/cm2/s (0.2-10 keV). 


UVOT took a finding chart exposure of 100 seconds with the White
(160-650 nm) filter starting 90 seconds after the BAT trigger. No
afterglow candidate has been found in the initial data products. The
2.7'x2.7' sub-image covers 25% of the BAT error circle and 100% of
the ground-determined XRT error circle. The typical 3-sigma upper
limit has been about 18.5 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 extinction.