GCN Circular 8355

D. Grupe (PSU), A. P. Beardmore (U Leicester),
P. A. Evans (U Leicester), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), J. A. Kennea (PSU),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),
D. M. Palmer (LANL), J. L. Racusin (PSU), M. Stamatikos (NASA/ORAU),
M. C. Stroh (PSU), T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU)
report on behalf of the Swift Team:

At 00:28:50 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 081011 (trigger=331332).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 220.361, +33.607 which is 
   RA(J2000) = 14h 41m 27s
   Dec(J2000) = +33d 36' 27"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single complex peak
structure with a duration of about 15 sec.  The peak count rate
was ~1100 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 00:30:24.4 UT, 93.9 seconds after
the BAT trigger. No source was detected in the promptly available XRT
data. This is highly unusual for a long GRB  
with a prompt Swift slew.  We are waiting for the full dataset 
to detect and localise the XRT counterpart. 


UVOT took a finding chart exposure of 150 seconds with the White (160-650 nm)
filter starting 98 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. 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 the expected extinction corresponding to E(B-V) of
0.01. 




Burst Advocate for this burst is D. Grupe (grupe AT astro.psu.edu). 
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.)