GCN Circular 7800

V. La Parola (INAF-IASFPA), P. A. Evans (U Leicester),
N. Gehrels (NASA/GSFC), C. Guidorzi (INAF-OAB),
S. T. Holland (CRESST/USRA/GSFC), N. P. M. Kuin (MSSL),
J. Mao (INAF-OAB), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
D. Perez (U Leicester), B. Sbarufatti (INAF-IASFPA),
R. L. C. Starling (U Leicester), D. E. Vanden Berk (PSU) and
H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:

At 07:27:01 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080604 (trigger=313116).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 236.970, +20.555 which is 
   RA(J2000) = 15h 47m 53s
   Dec(J2000) = +20d 33' 19"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a broad single peak
structure with a duration of about 70 sec.  The peak count rate
was ~300 counts/sec (15-350 keV), at ~10 sec after the trigger. 

The XRT began observing the field at 07:29:00.4 UT, 119.3 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 236.9648, +20.5572 which is equivalent to:
   RA(J2000)  = 15h 47m 51.5s
   Dec(J2000) = +20d 33' 25.9"
with an uncertainty of 5.4 arcseconds (radius, 90% containment). This
location is 19 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy. 


UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm)
filter starting 128 seconds after the BAT trigger. There is a candidate
afterglow in the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  =	15:47:51.70 = 236.9654
  DEC(J2000) = +20:33:28.1  =  20.5578
with a 1-sigma error radius of about 0.5 arc sec. This position is 3.4 arc sec. 
from the center of the XRT error circle. The estimated magnitude is 20.1 with a
1-sigma error of about 0.5 mag. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.05. 




Burst Advocate for this burst is V. La Parola (laparola AT ifc.inaf.it). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)