TITLE: GCN CIRCULAR NUMBER: 6491 SUBJECT: GRB 070610, Swift-BAT refined analysis DATE: 07/06/11 00:01:17 GMT FROM: Scott Barthelmy at NASA/GSFC J. Tueller (GSFC), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), C. Pagani (PSU), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+427 sec from the recent telemetry downlink, we report further analysis of BAT GRB 070610 (trigger #281993) (Pagani, et al., GCN Circ. 6489). The BAT ground-calculated position is RA, Dec = 298.805, 26.256 deg which is RA(J2000) = 19h 55m 13.1s Dec(J2000) = 26d 15' 20" with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 52%. The mask-weighted light curve shows a single peak starting at ~T-2 sec and ending at ~T+6 sec. T90 (15-350 keV) is 4.6 +- 0.4 sec (estimated error including systematics). The time-averaged spectrum from T-0.8 to T+4.4 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.76 +- 0.25. The fluence in the 15-150 keV band is 2.4 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+1.76 sec in the 15-150 keV band is 0.9 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.