TITLE:   GCN CIRCULAR
NUMBER:  31707
SUBJECT: GRB 220306B: Swift-BAT refined analysis
DATE:    22/03/07 20:22:04 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

S. D. Barthelmy (GSFC), R. Caputo (GSFC)
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),
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 220306B (trigger #1095288)
(Caputo et al., GCN Circ. 31697).  The BAT ground-calculated position is
RA, Dec = 5.380, 71.384 deg which is
   RA(J2000)  =  00h 21m 31.3s
   Dec(J2000) = +71d 23' 04.1"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 78%.

The mask-weighted light curve shows a single-peaked structure that starts
at ~T-2 s, peaks at ~T0, and ends at ~T+12 s. T90 (15-350 keV) is
12.34 +- 3.24 sec (estimated error including systematics).

The time-averaged spectrum from T-1.82 to T+11.66 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
1.30 +- 0.20.  The fluence in the 15-150 keV band is 6.0 +- 0.7 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T-0.05 sec in the 15-150 keV band
is 2.3 +- 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/1095288/BA/