TITLE:   GCN CIRCULAR
NUMBER:  23442
SUBJECT: GRB 181123A, Swift-BAT refined analysis
DATE:    18/11/23 21:28:55 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), 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 181123A (trigger #873178)
(Lien et al., GCN Circ. 23431).  The BAT ground-calculated position is
RA, Dec = 284.753, -8.208 deg which is
  RA(J2000)  =  18h 58m 36.2s
  Dec(J2000) = -08d 14' 14.3"
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows some weak emission that starts at ~ T-60 s
and ends at ~T+190 s. T90 (15-350 keV) is 220.9 +- 55.9 sec (estimated error
including systematics).

The time-averaged spectrum from T-61.3 to T+187.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.88 +- 0.31.  The fluence in the 15-150 keV band is 9.9 +- 1.6 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-36.46 sec in the 15-150 keV band
is 0.3 +- 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/873178/BA/