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GCN Circular 33280

Subject

GRB 230205A: Swift-BAT refined analysis (T90 = 2.3 s)

Date

2023-02-06T04:14:03Z (2 years ago)

From

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

T. Sakamoto (AGU), E. Ambrosi (INAF-IASFPA),
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. Parsotan (GSFC/UMBC), M. Stamatikos (OSU)
(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 230205A (trigger #1152764)
(Ambrosi et al., GCN Circ. 33271Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 202.057, 46.686 deg which is
   RA(J2000)  =  13h 28m 13.7s
   Dec(J2000) = +46d 41' 08.1"
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a short pulse that starts at ~T0,
peaks at ~T+2 s, and ends at ~T+3 s. In addition, there may be some
hint of extended emission that lasts till ~T+80 s. T90 (15-350 keV)
is 2.30 +- 0.36 sec (estimated error including systematics).

The time-averaged spectrum from T+0.32 to T+2.87 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.44 +- 0.29.  The fluence in the 15-150 keV band is 1.6 +- 0.3 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T+1.74 sec in the 15-150 keV band
is 0.9 +- 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/1152764/BA/