TITLE:   GCN CIRCULAR
NUMBER:  34134
SUBJECT: GRB 230628E: Swift-BAT refined analysis
DATE:    23/07/02 13:03:50 GMT
FROM:    Sibasish Laha at GSFC <sibasish.laha@nasa.gov>

T. Parsotan (GSFC/UMBC), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
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 230628E (trigger #1177054)
(Salvaggio et al., GCN Circ. 34110).  The BAT ground-calculated position is
RA, Dec = 171.851, -11.430 deg which is
   RA(J2000)  =  11h 27m 24.3s
   Dec(J2000) = -11d 25' 46.5"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 41%.

The BAT  light curve shows a complex structure with a duration of ~ 15 sec.
T90 (15-350 keV) is 4.72 +- 1.08 sec (estimated error including systematics).

The time-averaged spectrum from T-0.50 to T+4.81 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.45 +- 0.30.  The fluence in the 15-150 keV band is 3.3 +- 0.6 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+0.33 sec in the 15-150 keV band
is 1.1 +- 0.3 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/1177054/BA/