TITLE: GCN CIRCULAR NUMBER: 8661 SUBJECT: GRB 081211B(?): Possible burst detection from Swift-BAT slew data DATE: 08/12/12 04:06:51 GMT FROM: Antonio Copete at Harvard U A. Copete, J. Grindlay (Harvard) S. Barthelmy, C. Markwardt, N. Gehrels (NASA/GSFC) We report the detection of a likely GRB candidate by the BAT Slew Survey (BATSS) in the slew that started on 12/11/08 at 06:15:02 UT and lasted 121 sec. The ground-calculated position is RA, Dec = 168.231, +53.845 deg, which is RA (J2000) = 11h 12m 55s Dec(J2000) = +53d 50' 43" with an uncertainty of 3.04 arcmin (90% confidence, including systematics). The detection was triggered by simultaneous detections of 7.4 sigma and 8.3 sigma from imaging in the overlapping energy bands of 15-50 keV and 15-150 keV, respectively. The burst mask-tagged lightcurve in the 15-150keV band shows two possible broad peaks in its emission profile that span the entire 102 sec that the source remains within the BAT field-of-view, starting at T+18 sec, and peaking T+34 and T+69 sec, suggesting that this is possibly the tail end of the prompt emission of a burst at that location. The time-averaged spectrum over the 102 sec of exposure of the source is best fit by a simple power law with photon index 1.73, and the fluence in the 15-150 keV band is 6.1 x 10^-7 erg/cm^2 A follow-up Swift ToO observation has been scheduled to begin on 12/12/08 at 04:51 UT, 22.6 hours after the burst. Optical/IR observations of this potential GRB are encouraged immediately, as it is well positioned for northern hemisphere observers.