TITLE: GCN CIRCULAR NUMBER: 5704 SUBJECT: GRB 061006: Swift-BAT refined analysis of the short-hard burst DATE: 06/10/07 05:56:21 GMT FROM: David Palmer at LANL 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). 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). 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.