TITLE:   GCN CIRCULAR
NUMBER:  6074
SUBJECT: GRB 070208: Swift detection of a burst
DATE:    07/02/08 09:34:19 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

G. Sato (GSFC/ISAS), S. D. Barthelmy (GSFC), S. Campana (INAF-OAB),
M. L. Conciatore (ASDC), P. A. Evans (U Leicester),
N. Gehrels (NASA/GSFC), C. Gronwall (PSU),
C. Guidorzi (Univ Bicocca&INAF-OAB), V. Mangano (INAF-IASFPA),
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. Stratta (ASDC),
G. Tagliaferri (INAF-OAB), S. D. Vergani (DIAS-DCU) and
H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:

At 09:10:34 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 070208 (trigger=259714).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 197.920, +61.959 which is 
   RA(J2000)  =  13h 11m 41s
   Dec(J2000) = +61d 57' 31"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single peak structure
with a duration of about 2 sec.  The peak count rate
was ~1200 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began taking data at 09:12:29 UT, 116 seconds after the BAT
trigger.  XRT could not centroid onboard, however in a 222 s ground-processed 
image, we found a previously uncatalogued X-ray source in the field of view at
the following coordinates:
RA(J2000) = 13h 11m 32.77s
Dec(J2000)= +61d 57' 55.17"
with an uncertainty of 5 arcseconds radius (90% containment). 
This position lies 63 arcseconds from the center of the BAT error circle. 
The approximate initial flux is 1.044e-11 erg/cm2/sec (0.2-10 keV). 

UVOT took a finding chart exposure of 100 seconds with the White
(160-650 nm) filter starting 119 seconds after the BAT trigger. No
afterglow candidate has been found in the initial data products. The
2.7'x2.7' sub-image covers 100% of the 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 XRT 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 0.01.