TITLE:   GCN CIRCULAR
NUMBER:  22833
SUBJECT: GRB 180623A: Swift-BAT refined analysis
DATE:    18/06/24 15:48:24 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), K. L. Page (U Leicester),
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-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180623A (trigger #844015)
(Page et al., GCN Circ. 22828).  The BAT ground-calculated position is
RA, Dec = 214.528, -60.268 deg which is
  RA(J2000)  =  14h 18m 06.8s
  Dec(J2000) = -60d 16' 05.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 63%.

The mask-weighted light curve shows a multi-peaked structure that starts
at ~T-60 s and ends at ~T+115 s. The three main peaks occur at ~T0, ~T+25 s,
and ~T+60 s, respectively. T90 (15-350 keV) is 114.9 +- 6.8 sec (estimated
error including systematics). Note that the burst entered the BAT FOV around
~ T-90 s. Therefore, there might be additional burst emission beforehand.

The time-averaged spectrum from T-61.8 to T+114.1 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.45 +- 0.04.  The fluence in the 15-150 keV band is 1.2 +- 0.02 x 10^-5 erg/cm2.
The 1-sec peak photon flux measured from T+59.11 sec in the 15-150 keV band
is 5.6 +- 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/844015/BA/