TITLE: GCN CIRCULAR NUMBER: 22938 SUBJECT: GRB 180709A: Swift-BAT refined analysis DATE: 18/07/09 20:48:13 GMT FROM: Amy Lien at GSFC M. Stamatikos (OSU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-240 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 180709A (trigger #846868) (Marshall et al., GCN Circ. 22930). The BAT ground-calculated position is RA, Dec = 38.086, 60.333 deg which is RA(J2000) = 02h 32m 20.7s Dec(J2000) = +60d 19' 59.4" with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 81%. The mask-weighted light curve shows a single-peaked structure that starts at ~T0 and peaks at ~T+10 s. The main structure ends at ~T+40 s, with some tail emission lasting till ~T+240 s. T90 (15-350 keV) is 215.1 +- 28.9 sec (estimated error including systematics). The time-averaged spectrum from T+0.54 to T+243.46 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.37 +- 0.23. The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+8.73 sec in the 15-150 keV band is 0.6 +- 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/846868/BA/