GCN Circular 32414
Subject
GRB 220715B: Swift-BAT refined analysis
Date
2022-07-18T20:12:06Z (2 years ago)
From
Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>
A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU), M. Stamatikos (OSU),
E. Troja (NASA/GSFC/UMCP), (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 220715B (trigger #1116441)
(Troja, et al., GCN Circ. 32405). The BAT ground-calculated position is
RA, Dec = 254.860, -33.586 deg which is
RA(J2000) = 16h 59m 26.5s
Dec(J2000) = -33d 35' 10.3"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 95%.
The mask-weighted light curve shows an initial pulse with a FRED shape,
Beginning at just before T+0 and extending to about T+20. There is a second
weaker, softer pulse centered just after T+40 sec. There are a few gaps in the
light curve data, but none appear to correspond to burst activity.
T90 (15-350 keV) is 40.40 +- 1.24 sec (estimated error including systematics).
The time-averaged spectrum from T-0.15 to T+42.17 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.36 +- 0.11. The fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.08 sec in the 15-150 keV band
is 1.3 +- 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/1116441/BA/