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GCN Circular 32374

Subject

GRB 220711B: Swift-BAT refined analysis

Date

2022-07-12T16:35:07Z (2 years ago)

From

Amy Lien at GSFC <amy.y.lien@nasa.gov>

H. A. Krimm (NSF), S. D. Barthelmy (GSFC),
A. D'Ai (INAF-IASFPA), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),
T. Sakamoto (AGU), M. Stamatikos (OSU)
(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 220711B (trigger #1115766)
(D'Ai et al., GCN Circ. 32366Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 262.018, 24.674 deg which is
   RA(J2000)  =  17h 28m 04.3s
   Dec(J2000) = +24d 40' 27.1"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 19%.

The mask-weighted light curve shows a multi-peaked structure that
starts at ~T-40 s and ends at ~T+100 s. The main peak occurs at ~T0.
T90 (15-350 keV) is 88.64 +- 19.96 sec (estimated error including
systematics).

The time-averaged spectrum from T-37.72 to T+98.89 sec is best fit
by a simple power-law model.  The power law index of the time-averaged
spectrum is 1.75 +- 0.08.  The fluence in the 15-150 keV band
is 6.0 +- 0.3 x 10^-6 erg/cm2. The 1-sec peak photon flux measured
from T-0.02 sec in the 15-150 keV band is 3.0 +- 0.4 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/1115766/BA/