GCN Circular 5704

H. Krimm (GSFC/USRA),  L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (BYU-Idaho), M. Koss (GSFC/UMD), C. Markwardt (GSFC/UMD),
D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU),
G. Sato (GSFC/ISAS), P. Schady (MSSL-UCL), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), on behalf of the Swift-BAT team:

Using the data set from T-240 to T+300 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 061006 (trigger #232585)
(Schady, et al., GCN Circ. 5699
Not found
 
 
).  The BAT ground-calculated
position is (RA,Dec) = 110.998,-79.195 {07h 23m 59.6s , -79d 11' 42"}
[deg; J2000] +-1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 73 %.

This burst began with an intense double-spike from T-22.8 to T-22.3  
seconds.
This spike was also seen as a short GRB by RHESSI, Konus, and Suzaku
(Hurley et al., GCN 5702
Not found
 
 
).  This was followed by lower-level persistent
emission at least until ~T+110 seconds.   T90 (15-350 keV) is 130 +/-  
10 s
(estimated error including systematics).

The power law index of the time-averaged spectrum of the entire burst
is 1.74 +/- 0.17 .  The fluence in the 15-150 keV band is
(1.43 +/- 0.14) x 10^-6 erg/cm2.
The peak 1-sec interval measured from T-23.2 sec, including the initial
spikes, has a power law index of 0.93 +/- 0.07 with a photon flux in the
15-150 keV band of 5.36 +/- 0.22 ph/cm2/sec.
All the quoted errors are at the 90% confidence level.

Because the initial spikes occurred during a preplanned slew, BAT
did not trigger until it had analyzed the first 64 second image  
following
the slew, which contained only this persistent emission.

This light curve of a hard spike followed by a softer persistent  
emission
is characteristic of BAT observations of the 'Short-Hard' class of GRBs.