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GCN Circular 26003

Subject
GRB 191011A: Swift-BAT refined analysis
Date
2019-10-12T01:36:12Z (5 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), J. P. Norris (BSU),
D. M. Palmer (LANL), 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 191011A (trigger #928924)
(Laha et al., GCN Circ. 25988).  The BAT ground-calculated position is
RA, Dec = 44.729, -27.853 deg which is
   RA(J2000)  =  02h 58m 55.0s
   Dec(J2000) = -27d 51' 12.4"
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.

The mask-weighted light curve shows a short pulse that starts and peaks
at ~T0, and ends at ~T+2 s. The short pulse is followed by some weak
emission
that lasts until ~T+8 s. T90 (15-350 keV) is 7.37 +- 0.95 sec (estimated
error
including systematics).

The time-averaged spectrum from T-0.21 to T+8.04 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.94 +- 0.17.  The fluence in the 15-150 keV band is 3.3 +- 0.4 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T+0.18 sec in the 15-150 keV band
is 1.8 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

Using the 16-ms binned light curve, the spectral lag of the short pulse
is 30 (+45, -34) ms for the 50-100 keV to 15-25 keV bands, and 20 (+40,
-44) ms
for the 25-50 keV to 15-25 keV bands. These values are consistent with
both short and long GRBs due to the large uncertainties.


The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/928924/BA/
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