TITLE: GCN CIRCULAR NUMBER: 36657 SUBJECT: EXO 0748-676: Swift-BAT refined analysis DATE: 24/06/10 22:17:46 GMT FROM: Tyler Parsotan at NASA GSFC M. J. Moss (GSFC), S. D. Barthelmy (GSFC), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU)(i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of EXO 0748-676 (trigger #1236151) (D’Elia, et al., GCN Circ. 36653). The BAT ground-calculated position is RA, Dec = 117.083, -67.777 deg which is RA(J2000) = 07h 48m 20.0s Dec(J2000) = -67d 46' 35.5" with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 92%. The mask-weighted lightcurve shows a fast rise exponential decay profile in the 15-25 keV energy range. T90 (15-350 keV) is 8.06 +- 2.52 sec (estimated error including systematics). The time-averaged spectrum from T-1.45 to T+7.90 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 5.07 +- 0.86. The fluence in the 15-150 keV band is 7.4 +- 1.7 x 10^-08 erg/cm2. The 1-sec peak photon flux measured from T+0.90 sec in the 15-150 keV band is 0.3 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1236151