GCN Circular 6411

S. D. Vergani (DIAS-DCU), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
S. Campana (INAF-OAB), M. M. Chester (PSU),
G. Cusumano (INAF-IASFPA), P. A. Evans (U Leicester),
N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA),
W. B. Landsman (NASA/GSFC), V. Mangano (INAF-IASFPA),
A. Moretti (INAF-OAB), P. T. O'Brien (U Leicester),
J. P. Osborne (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), P. Romano (Univ. Bicocca & INAF-OAB),
G. Sato (GSFC/ISAS), B. Sbarufatti (INAF-IASFPA),
M. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester),
G. Tagliaferri (INAF-OAB), E. Troja (INAF-IASFPA) and
H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:

At 11:20:58 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 070517 (trigger=279494).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 277.579, -62.333 which is 
   RA(J2000)  =  18h 30m 19s
   Dec(J2000) = -62d 19' 56"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows two peaks
with a duration of about 10 sec.  The peak count rate
was ~1000 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began taking data at 11:22:43 UT, 105 seconds after the BAT
trigger. The XRT on-board centroid algorithm did not find a source in
the image, but analysis of down-linked data yields a position:  
  RA(J2000) = 18h 30m 29.4s   
  Dec(J2000) = -62d 17' 50.8" 
with an uncertainty of 5.2 arcsec (radius, 90% containment). 
This position is  2.4 arcmin from the BAT position. 

The UVOT is unable to observe the field of GRB070517 due to the
presence of a 4th magnitude star 8 arcmin from the burst's location. 
The Galactic reddening in the direction of the burst is E(B-V) =
0.15.