GCN Circular 6326

M. Stamatikos (GSFC/ORAU), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J.
Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm
(GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), J. Tueller (GSFC) on behalf of
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 070419A
(trigger #276205)  (Stamatikos, et al., GCN Circ. 6302
Not found
 
 
).  The BAT
ground-calculated position
is RA, Dec = 182.755, 39.903 deg which is 
   RA(J2000) = 12h 11m 1.1s 
   Dec(J2000) = 39d 54' 11.0" 
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The
coding fraction was 1.

This position is ~1.5 arcmin from the position of the optical afterglow
candidate reported by Chornock et al. (GCN Circ 6304
Not found
 
 
), which was further
confirmed by Cenko et al. (GCN Circ 6306
Not found
 
 
). 
 
The mask-weighted light curve has a nearly symmetric, smooth profile,
although a tail of emission extends to about T+160 sec. The T90 (15-350 keV)
is ~116 +- 6 sec (estimated error including systematics).
 
The time-averaged spectrum, from T-35 to T+93, is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is 2.35
+- 0.25. The fluence in the 15-150 keV band is 5.6 +- 0.8 x 10^-7 erg/cm^2.
The 1-sec peak photon flux measured from T-1.12 sec in the 15-150 keV band
is 2.8 x 10^-2 ph/cm^2/sec.  All the quoted errors are at the 90% confidence
level.

Under a Lambda Cold Dark Matter cosmological model, with Ho ~ 65 km/Mpc/s,
Omega_M ~ 0.30, and Omega_Lambda ~ 0.70, the preliminary Keck absorption
redshift of 0.97, reported by Cenko et al. (GCN Circ 6322
Not found
 
 
), when coupled to
the BAT fluence reported above, results in a preliminary isotropic energy
emission estimate of ~ 1.60 x 10^+51 ergs in the 15-150 keV observed (30-296
keV GRB rest frame) band pass.