| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 7920
SUBJECT: GRB 080702: Swift detection of a short burst
DATE: 08/07/02 12:10:31 GMT
FROM: David Palmer at LANL
M. De Pasquale (UCL-MSSL), W. H. Baumgartner (GSFC/UMBC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
C. Guidorzi (INAF-OAB), J. A. Kennea (PSU), V. Mangano (INAF-IASFPA),
F. E. Marshall (NASA/GSFC), C. Pagani (PSU), K. L. Page (U Leicester),
D. M. Palmer (LANL), P. Romano (INAF-IASFPA), T. Sakamoto (NASA/UMBC),
B. Sbarufatti (INAF-IASFPA), P. Schady (MSSL-UCL),
M. Stamatikos (NASA/ORAU), E. Troja (INAF-IASFPA),
T. N. Ukwatta (GSFC/GWU) and P. A. Ward (MSSL-UCL) report on behalf
of the Swift Team:
At 11:50:43 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080702 (trigger=315710). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 312.853, +72.308 which is
RA(J2000) = 20h 51m 25s
Dec(J2000) = +72d 18' 28"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a double-peaked
structure with the second peak larger and a total duration of
about 1.5 sec. The peak count rate was ~3000 counts/sec (15-350 keV),
at ~0.5 sec after the trigger, during the second peak.
The XRT began observing the field at 11:51:50.0 UT, 66.3 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 313.05101,
72.31271 which is equivalent to:
RA(J2000) = 20h 52m 12.24s
Dec(J2000) = +72d 18' 45.8"
with an uncertainty of 3.0 arcseconds (radius, 90% containment). This
location is 217 arcseconds from the BAT onboard position, slightly outside 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
1.53e+21 cm^-2 (Kalberla et al. 2005).
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm)
filter starting 72 seconds after the BAT trigger. No afterglow candidate has
been found in the initial data products. The XRT position is outside the
2.7'x2.7' sub-image. 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 0.67.
Burst Advocate for this burst is M. De Pasquale (mdp AT mssl.ucl.ac.uk).
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.)
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