GCN Circular 8030

W. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC),
E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), K. McLean (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)
(i.e. the Swift-BAT team):
 
Using the data set from T-120 to T+182 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 080727B (trigger #318101)
(Immler, et al., GCN Circ. 8022
Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 276.871, 1.173 deg which is 
   RA(J2000)  =  18h 27m 29.1s 
   Dec(J2000) = +01d 10' 23.2" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 69%.
 
The mask-weighted light curve shows two big FRED-like pulses from 
T-0.5 to T+3 sec and from T+5.5 to T+9.5 sec.  There are several 
pulses starting at T+2.5, T+7.2, T+7.5, and T+8.8 sec.  
T90 (15-350 keV) is 8.6 +- 0.2 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.2 to T+9.4 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.80 +- 0.17, 
and Epeak of 226.6 +- 120.2 keV (chi squared 43.60 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 3.1 +- 0.1 x 10^-06 erg/cm2
and the 1-sec peak flux measured from T-0.04 sec in the 15-150 keV band is
7.6 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.12 +- 0.04 (chi squared 54.09 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/318101/BA/