[vsnet-grb-info 27794] GRB 210422A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29897
SUBJECT: GRB 210422A: Swift-BAT refined analysis
DATE:    21/04/25 00:00:01 GMT
FROM:    Sibasish Laha at GSFC  <sibasish.laha at nasa.gov>

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),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(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 210422A (trigger #1044678)
(Troja et al., GCN Circ. 29886).  The BAT ground-calculated position is
RA, Dec = 21.077, 42.100 deg which is
   RA(J2000)  =  01h 24m 18.6s
   Dec(J2000) = +42d 05' 58.2"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 53%.

The BAT light curve showed a complex structure with a duration of about ~30 sec.
T90 (15-350 keV) is 39.00 +- 7.28 sec (estimated error including systematics).

The time-averaged spectrum from -34.40 s to -20.56 s and -19.40s to 7.59 s is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.70 +- 0.22.  The fluence in the 15-150 keV band is 7.2 +- 1.1 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+0.59 sec in the 15-150 keV band
is 1.3 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
https://swift.gsfc.nasa.gov/results/BATbursts/1044678/bascript/top.html