Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to https://gcn.nasa.gov.
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 3964

Subject
GRB 050911: Swift-BAT refined analysis
Date
2005-09-11T19:24:11Z (19 years ago)
From
Takanori Sakamoto at NASA/GSFC <takanori@milkyway.gsfc.nasa.gov>
J. Tueller (GSFC), L. Barbier (GSFC), S. Barthelmy (GSFC), 
M. Chester (PSU), J. Cummings (GSFC/NRC), E. Fenimore (LANL), 
N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), 
C. Markwardt (GSFC/UMD), F. Marshall (GSFC), D. Palmer (LANL), 
A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), 
on behalf of the Swift-BAT team:

Using the data set from T-60 to T+120 sec from the recent telemetry
downlink, we report further analysis of Swift-BAT GRB 050911
(trigger #154630)  (Page, et al., GCN 3961).  The refined BAT ground 
position is (RA,Dec) = 13.718, -38.862 { 0h 54m 52.4s, -38d 51' 42.8"} 
[deg; J2000] +-2.8 arcmin, (radius, sys+stat, 90% containment).  
The partial coding was 43 %.  

The mask-weighted BAT light curves show at least three peaks.  
The first two peaks are at T-1 and T+0 sec, each with a duration of 
0.5 sec. The third peak is a slow rise and decay from T+10 to T+20 sec.   
The third peak is not appreciably softer than the first two, 
as suggested by Berger (GCN Circ 3962).  Thus the burst is very likely 
in the long GRB category.  T90 (15-350 keV) is (16 +- 2) sec.  
(estimated error including systematics).  

The power law index of the time-averaged spectrum is 1.87 +- 0.03.  
The fluence in the 15-150 keV band is (3.0 +- 0.6) x 10^-7 erg/cm2.  
The 1-sec peak photon flux measured from T0-0.1 sec in the 15-150 keV 
band is (1.3 +- 0.2) ph/cm2/sec.  All the quoted errors are at the 90% 
confidence level.
Looking for U.S. government information and services? Visit USA.gov