GCN Circular 40055
Subject
GRB 250330A Swift-BAT refined analysis
Date
2025-04-04T16:15:22Z (12 days ago)
From
Mike Moss at NASA GSFC <mikejmoss3@gmail.com>
Via
Web form
H. A. Krimm (NSF), S. D. Barthelmy (GSFC),
S. B. Cenko (GSFC), R. Gupta (GSFC),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
C. B. Markwardt (GSFC), M. J. Moss (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-137 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 250330A (trigger #1299776)
(Cenko, et al., GCN Circ. 39938). The BAT ground-calculated position is
RA, Dec = 252.685, -86.875 deg which is
RA(J2000) = 16h 50m 44.5s
Dec(J2000) = -86d 52' 29.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 98%.
The mask-weighted light curve shows a single well defined fast-rise exponential-
decay pulse shape. the T90 (15-350 keV) is 11.27 +- 2.53 sec (estimated error
including systematics).
The time-averaged spectrum from T-0.16 to T+14.33 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.72 +- 0.10. The fluence in the 15-150 keV band is 9.2 +- 0.6 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+0.26 sec in the 15-150 keV band
is 4.0 +- 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/1299776