TITLE:   GCN CIRCULAR
NUMBER:  23780
SUBJECT: GRB 190123A: Swift-BAT refined analysis
DATE:    19/01/24 12:20:11 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC),  J. R. Cummings (CPI),
A. D'Ai (INAF-IASFPA), H. A. Krimm (NSF/USRA), 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 190123A (trigger #885314)
(D'Ai, et al., GCN Circ. 23769).  The BAT ground-calculated position is
RA, Dec = 53.175, 45.505 deg, which is
   RA(J2000)  =  03h 32m 42.0s
   Dec(J2000) = +45d 30' 16.3"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 64%.

The mask-weighted light curve shows a single FRED-shaped peak from about
T-5 to T+20 sec, with a peak around T+3 sec.   Observations were discontinued
due to an observing constraint at ~T+325 sec.  T90 (15-350 keV) is
24.4 +- 4.3 sec (estimated error including systematics).

The time-averaged spectrum from T-1.22 to T+28.06 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.13 +- 0.23.  The fluence in the 15-150 keV band is 8.4 +- 1.1 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+4.82 sec in the 15-150 keV band
is 1.0 +- 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/885314/BA/