TITLE: GCN CIRCULAR NUMBER: 6121 SUBJECT: GRB 070220 Swift-BAT Refined Analysis DATE: 07/02/20 22:38:05 GMT FROM: Michael Stamatikos at GSFC A. Parsons (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), D. Palmer (LANL), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC) on behalf of the Swift-BAT team: Using the data set from T-240 to T+1000 sec from the recent telemetry downlink, we report further analysis of BAT GRB 070220 (trigger #261299) (Stamatikos, et al., GCN Circ. 6114). The BAT ground-calculated position is RA, Dec = 34.800, 68.800 deg which is RA(J2000) = 2h 19m 11.9s Dec(J2000) = 68d 48' 1.6" with an uncertainty of 1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 64%. The mask-weighted lightcurve shows a multiple peaked structure. T90 (15-350 keV) is 129 +- 6 sec (estimated error including systematics). The time-averaged spectrum from T-17 to T+240 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.45 +- 0.04. The fluence in the 15-150 keV band is 1.06 +- 0.02 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from T+12 sec in the 15-150 keV band is 5.88 +- 0.29 ph/cm2/sec. All the quoted errors are at the 90% confidence level.