GRB 110827A

B.-B. Zhang (PSU), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC),
C. Gronwall (PSU), D. Grupe (PSU), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Swift Team:

At 00:01:52 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 110827A (trigger=501520).  Swift could not slew to this
burst due to the Sun constraint.  The BAT on-board calculated location is 
RA, Dec 164.095, +53.787 which is 
   RA(J2000) = 10h 56m 23s
   Dec(J2000) = +53d 47' 13"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex
structure with a duration of about 30 sec.  The peak count rate
was ~600 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 2011 September 05. There will thus be no XRT
or UVOT data for this trigger before this time. 

Burst Advocate for this burst is B.-B. Zhang (bbzhang AT 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.)

T. Sakamoto (GSFC/UMBC), 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), D. M. Palmer (LANL),
G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC),
T. N. Ukwatta (MSU), B.-B. Zhang (PSU) (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 110827A (trigger #501520)
(Zhang, et al., GCN Circ. 12310
Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 164.059, 53.817 deg which is
     RA(J2000)  =  10h 56m 14.2s
     Dec(J2000) = +53d 49' 01.2"
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a single peak starting at ~T-15 sec,
peaking at T+5 sec and returning to background by T+35 sec.
At T+195 sec, a pre-planned slew moved the source out of the field of view.
T90 (15-350 keV) is 8.5 +- 1.1 sec (estimated error including systematics).

The time-averaged spectrum from T-2.9 to T+6.3 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.24 +- 0.27.  The fluence in the 15-150 keV band is 1.8 +- 0.3 x 10-07
erg/cm2. The 1-sec peak photon flux measured from T+2.12 sec in the 15-150 keV
band is 0.4 +- 0.1 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/501520/BA/