TITLE:   GCN CIRCULAR
NUMBER:  27578
SUBJECT: GRB 200410A: Swift-BAT refined analysis
DATE:    20/04/15 03:19:33 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
K. K. Simpson (PSU), 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 200410A (trigger #965638)
(Simpson et al., GCN Circ. 27518).  The BAT ground-calculated position is
RA, Dec = 299.644, 51.745 deg which is
   RA(J2000)  =  19h 58m 34.6s
   Dec(J2000) = +51d 44' 40.9"
with an uncertainty of 2.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 53%.

The mask-weighted light curve shows several weak pulses. The two main
pulses occur at ~T-20 s and ~T+2 s, respectively, followed by some weak
emission that lasts till ~T+50 s. T90 (15-350 keV) is 108.8 +- 40.7 sec
(estimated error including systematics).

The time-averaged spectrum from T-90.88 to T+50.62 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
1.41 +- 0.31.  The fluence in the 15-150 keV band is 1.2 +- 0.2 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+1.43 sec in the 15-150 keV band
is 1.8 +- 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/965638/BA/