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GCN Circular 30917

Subject

GRB 210930A: Swift-BAT refined analysis

Date

2021-10-01T18:22:49Z (3 years ago)

From

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

H. A. Krimm (NSF), S. D. Barthelmy (GSFC),
V. D'Elia (SSDC & INAF-OAR), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
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 210930A (trigger #1075565)
(D'Elia et al., GCN Circ. 30897Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 197.415, 48.630 deg which is
   RA(J2000)  =  13h 09m 39.5s
   Dec(J2000) = +48d 37' 47.1"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a single-pulse structure that
starts at ~T+6 s, peaks at ~T+9 s, and ends at ~T+20 s.
T90 (15-350 keV) is 11.81 +- 1.94 sec (estimated error including
systematics).

The time-averaged spectrum from T+5.84 to T+19.24 sec is best fit
by a simple power-law model.  The power law index of the time-averaged
spectrum is 1.58 +- 0.19.  The fluence in the 15-150 keV band is
4.0 +- 0.5 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from
T+8.40 sec in the 15-150 keV band is 0.7 +- 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/1075565/BA/