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GCN Circular 28179

Subject

GRB 200729A: Swift-BAT refined analysis

Date

2020-07-30T18:22:38Z (4 years ago)

From

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

H. A. Krimm (NSF), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), P. A. Evans (U Leicester),
S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 200729A
(trigger #984929) (Evans et al., GCN Circ. 28165Not found
 
 
).
The BAT ground-calculated position is
RA, Dec = 184.360, 45.571 deg which is
   RA(J2000)  =  12h 17m 26.5s
   Dec(J2000) = +45d 34' 13.9"
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 46%.

The mask-weighted light curve shows a weak pulse that starts at ~T0,
peaks at ~T+6 s, and ends at ~T+130 s. T90 (15-350 keV)
is 122.0 +- 34.2 sec (estimated error including systematics).

The time-averaged spectrum from T+0.54 to T+136.54 sec is best fit
by a simple power-law model.  The power law index of the time-averaged
spectrum is 0.96 +- 0.27.  The fluence in the 15-150 keV band
is 1.6 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured
from T+5.54 sec in the 15-150 keV band is 0.7 +- 0.3 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/984929/BA/