TITLE:   GCN CIRCULAR
NUMBER:  30863
SUBJECT: GRB 210919A: Swift-BAT refined analysis
DATE:    21/09/22 22:04:47 GMT
FROM:    Sibasish Laha at GSFC  <sibasish.laha@nasa.gov>

S. D. Barthelmy (GSFC), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tempa),
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 210919A (trigger #1073893)
(Tohuvavohu et al., GCN Circ. 30846).  The BAT ground-calculated position is
RA, Dec = 80.242, 1.286 deg which is
   RA(J2000)  =  05h 20m 58.1s
   Dec(J2000) = +01d 17' 08.8"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 50%.

The BAT light curve showed a short pulse of a duration ~ 1 sec.
T90 (15-350 keV) is 0.16 +- 0.03 sec (estimated error including systematics).

The time-averaged spectrum from T+0.05 to T+0.24 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.58 +- 0.27.  The fluence in the 15-150 keV band is 8.8 +- 1.7 x 10^-08 erg/cm2.
The 1-sec peak photon flux measured from T-0.35 sec in the 15-150 keV band
is 1.5 +- 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/1073893/BA/