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GCN Circular 32197

Subject
GRB 220611A: Swift-BAT refined analysis
Date
2022-06-13T22:36:11Z (2 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
S. B. Cenko (GSFC), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
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 220611A (trigger #1110090)
(Cenko et al., GCN Circ. 32191).  The BAT ground-calculated position is
RA, Dec = 66.505, -37.265 deg which is
   RA(J2000)  =  04h 26m 01.2s
   Dec(J2000) = -37d 15' 54.2"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 70%.

The mask-weighted light curve shows a weak pulse that starts at ~T0
and ends at ~T+60 s. There might be a possible precursor emission
(~ 5 sigma in the 15-350 keV image) from ~T-90 s to ~T-85 s.
T90 (15-350 keV) is 57.00 +- 12.37 sec (estimated error including
systematics).

The time-averaged spectrum from T+0.52 to T+61.52 sec is best fit
by a simple power-law model.  The power law index of the time-averaged
spectrum is 1.87 +- 0.29.  The fluence in the 15-150 keV band is
6.7 +- 1.3 x 10^-7 erg/cm2. 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/1110090/BA/
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