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GCN Circular 30554

Subject

GRB 210730A: Swift-BAT refined analysis

Date

2021-07-30T17:05:35Z (3 years ago)

From

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

T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), E. Sonbas (Adiyaman Univ.),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+200 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 210730A (trigger #1062150)
(Sonbas et al., GCN Circ. 30548Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 149.570, 69.703 deg which is
   RA(J2000)  =  09h 58m 16.8s
   Dec(J2000) = +69d 42' 12.4"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 55%.

The mask-weighted light curve shows a single-peaked structure that
starts at ~T-0.5, peaks at ~T+0.5, and ends at ~T+5. T90 (15-350 keV)
is 3.86 +- 0.66 sec (estimated error including systematics).

The time-averaged spectrum from T-0.32 to T+5.01 sec is best fit by
a simple power-law model.  The power law index of the time-averaged
spectrum is 1.41 +- 0.11.  The fluence in the 15-150 keV band
is 1.3 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured
from T+0.17 sec in the 15-150 keV band is 7.1 +- 0.5 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/1062150/BA/