GRB 240415A: Swift-BAT refined analysis

Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 240415A (trigger #1221874) (Moss, et al., GCN Circ. 36108). The BAT ground-calculated position is RA, Dec = 129.197, 73.150 deg which is RA(J2000) = 08h 36m 47.2s Dec(J2000) = +73d 09' 01.7" with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 60%. The mask-weighted light curve displays a bright pulse lasting for ~15 s and peaking at ~T0+5 s and another dim pulse of emission at ~T0+30 s. The T90 (15-350 keV) is 30.96 +- 3.59 sec (estimated error including systematics). The time-averaged spectrum from T-0.70 to T+37.50 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.28 +- 0.13. The fluence in the 15-150 keV band is 1.6 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+5.09 sec in the 15-150 keV band is 4.6 +- 0.4 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/1221874