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 <sibasish.laha@nasa.gov>

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