TITLE:   GCN CIRCULAR
NUMBER:  9167
SUBJECT: GRB 090419: Swift-BAT refined analysis
DATE:    09/04/20 01:33:40 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
G. Stratta (ASDC), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+704 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090419 (trigger #349592)
(Stratta, et al., GCN Circ. 9161).  The BAT ground-calculated position is
RA, Dec = 197.006, -75.615 deg, which is 
   RA(J2000)  =  13h 08m 01.5s 
   Dec(J2000) = -75d 36' 55.6" 
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.
 
The mask-weighted light curve shows a long burst with multiple peaks.
The first peak starts at ~T-30 sec.  There are comparably bright peaks
at T+50, 100, and 320 sec.  There is continued emmission out to at least T+1000 sec
and possibly T+1800 sec.  T90 (15-350 keV) is 450 +- 50 sec (estimated error
including systematics).
 
The time-averaged spectrum from T+8.1 to T+522.8 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.38 +- 0.16.  The fluence in the 15-150 keV band is 2.5 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+37.18 sec in the 15-150 keV band
is 0.4 +- 0.1 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/349592/BA/