GCN Circular 22447
Subject
GRB 180224A: Swift-BAT refined analysis
Date
2018-02-25T18:19:11Z (6 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 BAT GRB 180224A (trigger #811561)
(Lien et al., GCN Circ. 22442). The BAT ground-calculated position is
RA, Dec = 202.675, 38.073 deg which is
RA(J2000) = 13h 30m 41.9s
Dec(J2000) = +38d 04' 23.0"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 93%.
The mask-weighted light curve shows a FRED-like pulse that starts at ~ T0,
peaks at ~ T+1 s, and ends at ~T+15 s. T90 (15-350 keV) is 10.9 +- 3.6 sec
(estimated error including systematics).
The time-averaged spectrum from T-0.48 to T+14.57 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.11 +- 0.18. The fluence in the 15-150 keV band is 4.7 +- 0.5 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.40 sec in the 15-150 keV band
is 1.4 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/811561/BA/