TITLE: GCN CIRCULAR NUMBER: 9640 SUBJECT: GRB 090709A: Swift-BAT refined analysis DATE: 09/07/09 22:52:32 GMT FROM: Scott Barthelmy at NASA/GSFC T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. C. Morris (PSU), D. M. Palmer (LANL), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+505 sec from recent telemetry downlinks, we report further analysis of BAT GRB 090709A (trigger #356890) (Morris, et al., GCN Circ. 9625). The BAT ground-calculated position is RA, Dec = 289.944, 60.728 deg, which is RA(J2000) = 19h 19m 46.7s Dec(J2000) = +60d 43' 40.8" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 75%. The mask-weighted light curve shows a complex structure. It starts at ~T-80 sec, peaks at T-70 sec, and returns to almost background at ~T-20 sec. Then a series of overlapping peaks starts with the brightest centered at ~T+22 sec. Then begins an exponential decay with a series of decreases eventually returning to background level at ~T+270 sec. There two more peaks at ~T+330 and ~T+400 sec. A third peak is chopped off while still rising when the source went out of the BAT FOV at ~T+490 sec due to the spacecraft slewing because of an observing constraint. T90 (15-350 keV) is 89 +- 3 sec (estimated error including systematics). The time-averaged spectrum from T-66.7 to T+101.5 sec is well fit by simple power law. The power law index of the time-averaged spectrum is 1.22 +- 0.03. The fluence in the 15-150 keV band is 2.57 +- 0.03 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from T+21.80 sec in the 15-150 keV band is 7.8 +- 0.3 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/356890/BA/