TITLE: GCN CIRCULAR NUMBER: 36292 SUBJECT: GRB 240419B: Swift-BAT refined analysis DATE: 24/04/24 21:47:33 GMT FROM: Sibasish Laha at GSFC T. Sakamoto (AGU), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC),(i.e. the Swift-BAT team): Using the data set from T-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 240419B (trigger #1223072) (Dichiara, et al., GCN Circ. 36180). The BAT ground-calculated position is RA, Dec = 325.853, 4.299 deg which is RA(J2000) = 21h 43m 24.7s Dec(J2000) = +04d 17' 58.2" with an uncertainty of 3.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 43%. The BAT light curve shows a complex structure with a duration of ~ 150 sec. T90 (15-350 keV) is 132.16 +- 26.29 sec (estimated error including systematics). The time-averaged spectrum from T-3.3 to T+159.5 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.92 +- 0.09. The fluence in the 15-150 keV band is 4.1 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+116.36 sec in the 15-150 keV band is 2.4 +- 0.2 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/1223072