TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4260
SUBJECT: GRB 051111: Swift-BAT refined analysis
DATE:    05/11/11 15:08:54 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori@milkyway.gsfc.nasa.gov>

H. Krimm (GSFC/USRA), M. Ajello (MPE), L. Barbier (GSFC), 
S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), 
R. Fink (GSFC), N. Gehrels (GSFC), D. Hullinger (UMD), 
C. Markwardt (GSFC/UMD),D. Palmer (LANL), A. Parsons (GSFC), 
T. Sakamoto (GSFC/NRC), G. Sato (ISAS), J. Tueller (GSFC), 
on behalf of the Swift-BAT team:

Using the data set from T-300 to T+300 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 051111 
(trigger #163438)  (Sakamoto, et al., GCN 4248).  
The BAT ground-calculated position is 
(RA,Dec) = 348.134, +18.365 {23h 12m 32s, 18d 21' 54"} [deg; J2000]
+- 0.8 arcmin, (radius, sys+stat, 90% containment).  
The partial coding was 59%.  

The light curve has a FRED-like structure with the duration of 
the rising and the decay part of 10 sec and 40 sec, respectively.  
The emission might be extended untill T+80 sec.  Although there is 
a bump around T+5s in the 100-350 keV band, this bump is not visible 
below 100 keV.  T90 (15-350 keV) is (47 +- 1) sec 
(estimated error including systematics).  

The power law index of the time-averaged spectrum is 1.32 +- 0.06.  
The fluence in the 15-150 keV band is (3.9 +- 0.1) x 10^-6 erg/cm2.  
The 1-sec peak photon flux measured from T-0.56 sec in the 15-150 keV 
band is (2.5 +- 0.2) ph/cm2/sec.  All the quoted errors are at the 90% 
confidence level.