[vsnet-grb-info 20228] GRB 180111A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22324
SUBJECT: GRB 180111A: Swift-BAT refined analysis
DATE:    18/01/12 16:04:27 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at nasa.gov>

M. Stamatikos (OSU), 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),
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 180111A (trigger #804692)
(Lien et al., GCN Circ. 22318).  The BAT ground-calculated position is
RA, Dec = 149.782, 48.254 deg which is
  RA(J2000)  =  09h 59m 07.7s
  Dec(J2000) = +48d 15' 14.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 70%.

The mask-weighted light curve shows several overlapping pulses that starts
at ~ T0 and ends at ~ T+70 s. The main peak occurs at ~ T+ 14 s.
T90 (15-350 keV) is 50.6 +- 1.9 sec (estimated error including systematics).

The time-averaged spectrum from T-0.30 to T+68.59 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.30 +- 0.03.  The fluence in the 15-150 keV band is 1.02 +- 0.02 x 10^-5 erg/cm2.
The 1-sec peak photon flux measured from T+13.89 sec in the 15-150 keV band
is 4.9 +- 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/804692/BA/