TITLE: GCN CIRCULAR NUMBER: 5881 SUBJECT: GRB 061201: Swift detection of a short hard burst DATE: 06/12/01 16:24:30 GMT FROM: David Palmer at LANL F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), O. Godet (U Leicester), S. T. Holland (GSFC/USRA), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), W. B. Landsman (NASA/GSFC), V. Mangano (INAF-IASFPA), C. B. Markwardt (GSFC/UMD), K. M. McLean (LANL/UTD), A. Moretti (INAF-OAB), D. M. Palmer (LANL), S. B. Pandey (UCL-MSSL), A. M. Parsons (GSFC), T. Sakamoto (NASA/ORAU), R. L. C. Starling (U Leicester) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team: At 15:58:36 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 061201 (trigger=241840). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 331.972, -74.600 which is RA(J2000) = 22h 07m 53s Dec(J2000) = -74d 36' 01" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single peak with some sub-structure and total duration of about 2 sec. The peak count rate was ~20000 counts/sec (15-350 keV), at ~1 sec after the trigger. This is also a very hard burst with ~8000 counts/sec in the highest energy bin (100-350 keV) and ~1000 counts/sec in the lowest energy bin (15-25 keV). The XRT began taking data at 15:59:58 UT, 81 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image and no prompt position is available. Down-linked data show a variable source at position: RA(J2000) = 22h 08m 32.07s DEC(J2000) = -74d 34' 47.0" with 3.8" of uncertainty (90% confidence). This position lies 170 arcseconds from the BAT position. UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 86 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.08.