GRB 090709B

F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC),
D. N. Burrows (PSU), V. D'Elia (ASDC), P. A. Evans (U Leicester),
O. Godet (U Leicester), C. Guidorzi (U Ferrara),
S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU),
H. A. Krimm (CRESST/GSFC/USRA), K. L. Page (U Leicester),
D. M. Palmer (LANL), A. Rowlinson (U Leicester),
B. Sbarufatti (INAF-IASFPA), M. H. Siegel (PSU), M. A. Stark (PSU),
R. L. C. Starling (U Leicester) and T. N. Ukwatta (GSFC/GWU) report
on behalf of the Swift Team:

At 15:07:42 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090709B (trigger=356912).  Swift did not slew because
of Sun constraint.  The BAT on-board calculated location is 
RA, Dec 93.593, +64.085, which is 
   RA(J2000)  =  06h 14m 22s
   Dec(J2000) = +64d 05' 07"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single peak
with a duration of at least 10 sec.  The peak count rate
was ~1000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to a Sun constraint, Swift cannot slew to the BAT position until 
18th July 2009. There will thus be no immediate XRT or UVOT data for 
this trigger. 

Burst Advocate for this burst is F. E. Marshall (marshall 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.)

T. N. Ukwatta (GWU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), F. E. Marshall 
(NASA/GSFC),
D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
(i.e. the Swift-BAT team):

Using the data set from T-61 to T+242 sec from the recent telemetry 
downlink,
we report further analysis of BAT GRB 090709B (trigger #356912)
(Marshall et al., GCN Circ. 9633
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 ).  The BAT ground-calculated position is
RA, Dec = 93.522, 64.081 deg which is
   RA(J2000)  =  06h 14m 05.4s
   Dec(J2000) = +64d 04' 51.9"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 15%.

The mask-weighted light curve shows a main peak beginning at T-5 seconds 
and
continuing until T+10 sec.  There are then two much weaker peaks at 
approximately
T+25 and T+35 sec. At T+240 sec, a pre-planned spacecraft slew took the 
source
out of the BAT FOV. T90 (15-350 keV) is 27.2 +- 6.6 sec (estimated error 
including systematics).

The time-averaged spectrum from T-5.4 to T+35.9 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.51 +- 0.18.  The fluence in the 15-150 keV band is 1.5 +- 0.2 x 10-6 
erg/cm2.
The 1-sec peak photon flux measured from T+1.47 sec in the 15-150 keV band
is 2.1 +- 0.4 ph/cm2/sec.  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/356912/BA/

C. Meegan (USRA) and A. J. van der Horst (NASA/MSFC/ORAU) 
report on behalf of the Fermi GBM Team: 

"At 15:07:41.14 UT on 09 July 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090709B (trigger 268844863 / 090709630), 
which was also detected by the SWIFT-BAT (GCN 9633
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 ).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 35 degrees.

The GBM light curve consists of two pulses
with a duration (T90) of about 32 s (8-1000 keV). 
The time-averaged spectrum from T0-2.0 s to T0+27.6 s is 
best fit by a power law function with an exponential
high energy cutoff.  The power law index is -1.01 +/- 0.16 and
the cutoff energy, parameterized as Epeak, is 130 +/- 24 keV
(chi squared 354 for 365 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(1.3 +/- 0.2)E-6 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0+2.0 s in the 8-1000 keV band 
is 2.0 +/- 0.3 ph/s/cm^2.

The temporal and spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."