GRB 080915B

H. Ziaeepour (UCL-MSSL), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), J. Mao (INAF-OAB), P. T. O'Brien (U Leicester),
S. R. Oates (UCL-MSSL), J. P. Osborne (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL), A. M. Parsons (GSFC),
D. Perez (U Leicester), M. Perri (ASDC), T. Sakamoto (NASA/UMBC),
R. L. C. Starling (U Leicester), G. Stratta (ASDC) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:

At 15:53:35 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080915B (trigger=324805). The BAT on-board calculated 
location is RA, Dec 213.078, -11.473 which is 
   RA(J2000) = 14h 12m 19s
   Dec(J2000) = -11d 28' 23"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single FRED peak
structure with a duration of about 5 sec.  The peak count rate
was ~13,000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to the Solar observing constraint, Swift cannot slew to the 
BAT position until mid-December. There will thus be no XRT or 
UVOT data for this trigger. 

Burst Advocate for this burst is H. Ziaeepour (hz 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.)

K. McLean (GSFC/UMD), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU),
H. Ziaeepour (UCL-MSSL)
(i.e. the Swift-BAT team):
 
Using the data set from T-28 to T+930 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 080915B (trigger #324805)
(Ziaeepour, et al., GCN Circ. 8234
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 ).  The BAT ground-calculated position is
RA, Dec = 213.088, -11.491 deg, which is 
   RA(J2000)  =  14h 12m 21.2s 
   Dec(J2000) = -11d 29' 26.9" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 74%.
 
The mask-weighted light curve shows a roughly symmetric peak starting
at ~T-0.5 sec, peaking at ~T+0.6 sec, and ending at ~T+4.5 sec.
T90 (15-350 keV) is 3.9 +- 0.7 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.5 to T+6.1 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.48 +- 0.35, 
and Epeak of 42.3 +- 9.1 keV (chi squared 54.5 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 9.9 +- 0.6 x 10^-7 erg/cm2
and the 1-sec peak flux measured from T+0.18 sec in the 15-150 keV band is
8.5 +- 0.3 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 2.02 +- 0.08 (chi squared 62.6 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/324805/BA/