TITLE:   GCN CIRCULAR
NUMBER:  8059
SUBJECT: GRB 080805: Swift detection of a burst
DATE:    08/08/05 08:13:07 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

C. Pagani (PSU), W. H. Baumgartner (GSFC/UMBC), M. M. Chester (PSU),
J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester),
D. Grupe (PSU), C. Guidorzi (INAF-OAB),
S. T. Holland (CRESST/USRA/GSFC), J. Mao (INAF-OAB),
A. Moretti (INAF-OAB), K. L. Page (U Leicester), D. M. Palmer (LANL),
J. L. Racusin (PSU), P. Romano (INAF-IASFPA) and
H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:

At 07:41:34 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080805 (trigger=319036).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 314.231, -62.438 which is 
   RA(J2000) = 20h 56m 55s
   Dec(J2000) = -62d 26' 16"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a FRED-like
structure with a duration of about 50 sec.  The peak count rate
was ~2600 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 07:42:38.3 UT, 63.5 seconds after
the BAT trigger. Using promptly downlinked data we find a bright, fading
uncatalogued X-ray source located at RA, Dec 314.22273, -62.44433 which
is equivalent to:
   RA(J2000)  = 20h 56m 53.46s
   Dec(J2000) = -62d 26' 39.6"
with an uncertainty of 3.6 arcseconds (radius, 90% containment).  This position
is 26.6 arcseconds from the BAT position, within the BAT error circle. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
3.45e+20 cm^-2 (Kalberla et al. 2005). 

UVOT took a finding chart exposure of 100 seconds with the White 
(160-650 nm)  filter starting 74 seconds after the BAT trigger. No 
afterglow candidate is apparent in the initial data products. The 
2.7'x2.7' sub-image covers 25% of  the BAT error circle and 100% of 
the XRT error circle. The typical 3-sigma upper limit has been about 
 18.5 mag. 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 0.043. 

Burst Advocate for this burst is C. Pagani (pagani 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.)