TITLE: GCN CIRCULAR NUMBER: 19505 SUBJECT: Trigger 689353 (possible transient near Sgr A*), Swift-BAT refined analysis DATE: 16/06/07 21:27:11 GMT FROM: Amy Lien at GSFC H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT trigger #689353 (possible transient near Sgr A*; Barthelmy, et al., GCN Circ. 19499). The BAT ground-calculated position is RA, Dec = 266.507, -29.063 deg which is RA(J2000) = 17h 46m 01.6s Dec(J2000) = -29d 03' 47.3" with an uncertainty of 3.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 93%. The mask-weighted light curve shows some very weak emissions that starts before the source came into the BAT field of view, and extends beyond the end of the event data range. The Bayesian-block analysis failed to find the duration due to the lack of obvious light curve structure. The time-averaged spectrum from T+0.0 to T+344.0 sec (the BAT image-trigger interval) is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.00 +- 0.50. The fluence in the 15-150 keV band is 6.4 +- 2.0 x 10^-7 erg/cm2. All the quoted errors are at the 90% confidence level. Because of the low-significance detection (5.2 sigma), we cannot rule out the possibility of this detection is due to instrumental noise. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/689353/BA/