TITLE: GCN CIRCULAR NUMBER: 13961 SUBJECT: GRB 121108A, Swift-BAT refined analysis DATE: 12/11/09 14:24:40 GMT FROM: Tilan Ukwatta at MSU W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 121108A (trigger #537921) (Ukwatta, et al., GCN Circ. 13952). The BAT ground-calculated position is RA, Dec = 83.216, 54.520 deg which is RA(J2000) = 05h 32m 51.9s Dec(J2000) = +54d 31' 11.2" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 90%. BAT light curve shows two multi-peak episodes. First one starts at the trigger time and lasts for about 50 seconds and the second weak episode starts around T+130 seconds and lasts for about 40 seconds. T90 (15-350 keV) is 89 +- 48 sec (estimated error including systematics). The time-averaged spectrum from T-0.15 to T+137.98 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.28 +- 0.20. The fluence in the 15-150 keV band is 9.6 +- 1.2 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+43.18 sec in the 15-150 keV band is 1.6 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/537921/BA/