GCN Circular 22436
Subject
GRB 180222A: Swift-BAT refined analysis
Date
2018-02-22T21:35:52Z (6 years ago)
From
Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. K. Cannizzo (NASA/UMBC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+423 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180222A (trigger #811235)
(Cannizzo, et al., GCN Circ. 22433). The BAT ground-calculated position is
RA, Dec = 256.537, -36.819 deg which is
RA(J2000) = 17h 06m 08.8s
Dec(J2000) = -36d 49' 08.2"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 98%.
The mask-weighted light curve consists of a single FRED pulse beginning at ~T-8 sec,
peaking at T+0 sec and decaying to background by T+60 sec. T90 (15-350 keV) is
64.0 +- 22.6 sec (estimated error including systematics).
The time-averaged spectrum from -15.1 to 48.9 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.40 +- 0.21. The fluence in the 15-150 keV band is 7.9 +- 1.0 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+8.44 sec in the 15-150 keV band
is 0.4 +- 0.1 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/811235/BA/