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GCN Circular 32264

Subject

GRB 220623A: Swift-BAT refined analysis

Date

2022-06-24T18:49:10Z (2 years ago)

From

Tyler Parsotan at UMBC/GSFC/CRESST II <parsotat@umbc.edu>

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T. Parsotan (GSFC/UMBC), S. D. Barthelmy (GSFC), 
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), (i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+842 sec from the recent telemetry downlink, we report further analysis of BAT GRB 220623A (trigger #1111672) (Sbarufatti, et al., GCN Circ. 32243Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 145.459, 75.823 deg which is 
   RA(J2000)  =  09h 41m 50.1s 
   Dec(J2000) = +75d 49' 22.9" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 94%.
 
The BAT light curve showed a triple-peaked structure. One possible precursor peak occurred prior to the trigger, another occurred at the trigger time, and the final occurred 10 s post trigger. At ~40 s there may be broad emission as well.  T90 (15-350 keV) is 57.11 +- 8.53 sec (estimated error including systematics).
 
The time-averaged spectrum from -3.84 to 73.652 sec is best fit by a simple power-law model.  The power law index of the time-averaged spectrum is 1.33 +- 0.07.  The fluence in the 15-150 keV band is 3.5 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T-0.15 sec in the 15-150 keV band is 4.5 +- 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/1111672/BA/