[vsnet-grb-info 27458] GRB 210222B: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29561
SUBJECT: GRB 210222B: Swift-BAT refined analysis
DATE:    21/02/23 22:42:22 GMT
FROM:    Sibasish Laha at GSFC  <sibasish.laha at nasa.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), B. Sbarufatti (PSU)
M. Stamatikos (OSU), (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 210222B (trigger #1034325)
(Gropp et al., GCN Circ. 29545).  The BAT ground-calculated position is
RA, Dec = 154.631, -14.946 deg which is
   RA(J2000)  =  10h 18m 31.4s
   Dec(J2000) = -14d 56' 45.7"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 38%.

The BAT light curve showed a two peaked structure with a duration of about ~20 sec.
T90 (15-350 keV) is 12.82 +- 1.28 sec (estimated error including systematics).

The time-averaged spectrum from T-11.37 to T+2.72 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.37 +- 0.33.  The fluence in the 15-150 keV band is 3.4 +- 0.7 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+0.87 sec in the 15-150 keV band
is 1.4 +- 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/1034325/BA/