GRB 080822B

G. Sato (ISAS), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
S. T. Holland (CRESST/USRA/GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
K. McLean (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+903 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 080822B (trigger #321376)
(Holland, et al., GCN Circ. 8117
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 ).  The BAT ground-calculated position is
RA, Dec = 63.560, 25.760 deg, which is 
   RA(J2000)  =  04h 14m 14.5s 
   Dec(J2000) = +25d 45' 35.5" 
with an uncertainty of 3.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 82%.
 
The mask-weighted light curve shows weak emission starting around T-50 sec
and ending around T+70 sec.  T90 (15-350 keV) is 64 +- 20 sec
(estimated error including systematics).
 
The time-averaged spectrum from T+0.0 to T+64.0 sec is fit by a power law.
This fit gives a photon index 2.54 +- 0.5.  (chi squared 76.5 for 59 d.o.f.).
For this model the total fluence in the 15-150 keV band is 1.7 +- 0.6 x 10^-07
erg/cm2 and the 1-sec peak flux measured from T+0.00 sec in the 15-150 keV band
is 0.06 +- 0.02 ph/cm2/sec.  All the quoted errors are at the 90%
confidence level. 

We note that this is a weak detection for BAT and that we can not rule out
a non-burst explanation for this trigger.

MASTER-Net Team:

D.Kuvshinov, V. Lipunov, V.Kornilov,  E.Gorbovskoy,
A.Belinski, N.Shatskiy, N.Tyurina,
Sternberg Astronomical Institute, Moscow Union 'Optic'

A. Tlatov, I.Golubov
Kislovodsk Solar Station of the Pulkovo observatory

V.Krushinski, I.Zalognikh
Ural State University, Kourovka

S.Yazev, K.Ivanov
Irkutsk State University


MASTER  robotic Net (Moscow region, http://observ.pereplet.ru)
responded to GRB080822B (Holland  et al., GCN Circ 8117
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 ) by hand
  due to internet problem at the Moscow Region Site.
The first image was started at 2008-08-22 21:21:35 UT, 18m 43s  after the 
GRB time.
The unfiltered image is calibrated relative to USNO A2.0 (0.8 R + 0.2 B).
The robot did not find OT-candidate in error box.


T-Tgrb    Mean Time     Exposition     Limit   Coadd?

1123 s     1138 s          30 s         17.0      no

1123s      1692 s         25x30 s       18.8     yes


The message can be cited.
mailto: lipunov@sai.msu.ru

S. T. Holland (CRESST/USRA/GSFC), S. D. Barthelmy (GSFC),
J. R. Cummings (NASA/UMBC), V. Mangano (INAF-IASFPA),
F. E. Marshall (NASA/GSFC), C. Pagani (PSU), D. M. Palmer (LANL),
M. Perri (ASDC), B. Preger (ASDC), R. L. C. Starling (U Leicester)
and G. Stratta (ASDC) report on behalf of the Swift Team:

At 21:02:52 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080822B (trigger=321376).  Swift did not slew to this burst
because of the Moon observing constraint.  It will come out of Moon constraint
early 26 Aug 08 UT. 
The BAT on-board calculated location is 
RA, Dec 63.495, +25.743, which is 
   RA(J2000)  =  04h 13m 59s
   Dec(J2000) = +25d 44' 34"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT TDRSS light curve does not show anything
significant which is typical for an image trigger. 

Burst Advocate for this burst is S. T. Holland (sholland AT milkyway.gsfc.nasa.gov). 
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.)

[GCN OPS NOTE(22aug08): Per author's request, the missing "B" suffix on the
burst name was added.]