TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3730
SUBJECT: GRB 050801: Swift-BAT refined analysis
DATE:    05/08/02 03:50:15 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori@milkyway.gsfc.nasa.gov>

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

At 18:28:02 UT Swift-BAT detected GRB 050801 (trigger=148522)
(GCN Circ 3725, Band, et al.).  The refined BAT ground position
is (RA,Dec) = 204.140, -21.937 [deg; J2000] {13h36m33.6s,-21d59'14.7"} 
+-3 arcmin, (95% containment).  The partial coding was 99 %.  

The light curve shows two peaks which are separated by about 3 seconds.  
The second peak is weaker and has a softer spectrum than the first peak.
T90 (15-350 keV) is (20 +- 3) seconds (estimated error including 
systematics).  

The power law index of the time-averaged spectrum is 2.0 +- 0.2.  
The fluence in the 15-350 keV band is (4.4 +- 1.0) x 10^-7 erg/cm2.  
The 1-s peak photon flux measured from T0+0.27 second in the 15-350 keV 
band is (1.7 +- 0.2) ph/cm2/s.  All the quoted errors are at the 90% 
confidence level.