TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4879 SUBJECT: GRB 060313: Further analysis of the Swift-BAT bright short hard burst DATE: 06/03/14 00:11:51 GMT FROM: Scott Barthelmy at NASA/GSFC S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), J. Norris (GSFC), T. Sakamoto (GSFC/NRC), D. Palmer (LANL on behalf of the Swift-BAT team: Using the data set from T-300 to T+300 sec from additional telemetry downlinks, we report further analysis of BAT GRB 060313 (trigger #201487) (Pagani, et al., GCN 4867; Markwardt, et al., 4873). This short burst does not show any sign of extended emission in the T+1 to T+300 sec range at an upper limit of 0.001 cnt/detector/sec. This corresponds to a flux ratio upper limit between the initial peak and the peak of any potential extended emission of 2000. We reference SHBs 050724 and 051227 which had ratios of 46 and ~10, respectively. The lag analysis shows this burst to be cleanly in the short hard burst class (Norris and Bonnell, 2006, ApJ, accepted; see, Figure 3). Specifically, the measured lags are: 50-100 keV to 15-25 keV: 0.8 ms +- 0.6 ms 100-350 keV to 25-50 keV: 0.3 ms +- 0.7 ms We further note that the lightcurve has multiple structures. There are at least 20 statistically significant peaks with FWHM in the 5-15 msec range. There is no perdiodic structure in the lightcurve for at least the first 100 sec.