TITLE:   GCN CIRCULAR
NUMBER:  26939
SUBJECT: GRB 200127A: Swift-BAT refined analysis
DATE:    20/01/29 22:48:04 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

D. M. Palmer (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), M. J. Moss (GWU)
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):

Using the data set from T-240 to T+1079 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 200127A (trigger #952791)
(Moss et al., GCN Circ. 26895).  The BAT ground-calculated position is
RA, Dec = 295.206, 44.934 deg which is
   RA(J2000)  =  19h 40m 49.4s
   Dec(J2000) = +44d 56' 03.5"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 50%.

The mask-weighted light curve shows a long weak emission that starts
around ~T-150 s and ends at ~T+90 s. T90 (15-350 keV) is 216.9 +- 23.5 sec
(estimated error including systematics).

The time-averaged spectrum from T-144.22 to T+92.97 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
1.64 +- 0.19.  The fluence in the 15-150 keV band is 2.4 +- 0.3 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+41.80 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/952791/BA/