[vsnet-grb-info 21187] GRB 180930A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23286
SUBJECT: GRB 180930A: Swift-BAT refined analysis
DATE:    18/10/01 18:21:40 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm at nsf.gov>

S. D. Barthelmy (GSFC),  J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU), A. Tohuvavohu (PSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):

Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180930A (trigger #864584)
(Tohuvavohu, et al., GCN Circ. 23279).  The BAT ground-calculated position is
RA, Dec = 76.894, -25.124 deg which is 
  RA(J2000)  =  05h 07m 34.6s 
  Dec(J2000) = -25d 07' 25.6" 
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 87%.

The mask-weighted light curve shows a single episode of weak emission from 
T-4 sec to T+4 sec with several peaks. T90 (15-350 keV) is 6.80 +- 0.95 sec 
(estimated error including systematics).

The time-averaged spectrum from T-3.24 to T+4.20 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.86 +- 0.28.  The fluence in the 15-150 keV band is 2.1 +- 0.4 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.14 sec in the 15-150 keV band
is 0.9 +- 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/864584/BA/