[vsnet-grb-info 21931] GRB 190331A, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24030
SUBJECT: GRB 190331A, Swift-BAT refined analysis
DATE:    19/03/31 22:20:21 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at nasa.gov>

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

Using the data set from T-599 to T+986 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 190331A (trigger #895813)
(Page et al., GCN Circ. 24027).  The BAT ground-calculated position is
RA, Dec = 28.573, 27.635 deg which is
   RA(J2000)  =  01h 54m 17.4s
   Dec(J2000) = +27d 38' 06.8"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 82%.

The mask-weighted light curve shows a multi-peaked structure that starts
at ~T0 and ends at ~T+4.5. The main peak occurs at ~T0.
T90 (15-350 keV) is 4.3 +- 0.2 sec (estimated error including systematics).

The time-averaged spectrum from T-0.1 to T+4.5 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.24 +- 0.15.  The fluence in the 15-150 keV band is 4.5 +- 0.4 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T-0.06 sec in the 15-150 keV band
is 2.8 +- 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/895813/BA/