TITLE: GCN CIRCULAR NUMBER: 27924 SUBJECT: GRB 200612A: Swift-BAT refined analysis DATE: 20/06/13 01:19:49 GMT FROM: Sibasish Laha at GSFC C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), T. Sakamoto (AGU), E. Sonbas (Adiyaman Univ.), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 200612A (trigger #977310) (E. Sonbas et al., GCN Circ. 27915). The BAT ground-calculated position is RA, Dec = 302.691, -45.354 deg which is RA(J2000) = 20h 10m 45.8s Dec(J2000) = -45d 21' 12.7" with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 96%. The mask weighted light curve shows a complex structure. The overall structure starts at ~T-20 s and lasts till ~T+200 s. T90 (15-350 keV) is 171.48 +- 19.74 sec (estimated error including systematics). The time-averaged spectrum from T-11 to T+193 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.34 +- 0.09. The fluence in the 15-150 keV band is 3.8 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+4.03 sec in the 15-150 keV band is 0.7 +- 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/977310/BA/