[vsnet-grb-info 4502] GRB 070411, Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6274
SUBJECT: GRB 070411, Swift-BAT refined analysis
DATE:    07/04/12 02:25:31 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

C. Markwardt (GSFC/UMD), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), A. Moretti (INAF-OAB), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
 
Using the data set from T-119 to T+303 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 070411 (trigger #275087)
(Moretti, et al., GCN Circ. 6267).  The BAT ground-calculated position is
RA, Dec = 107.345, 1.051 deg which is 
   RA(J2000) = 7h 9m 22.9s 
   Dec(J2000) = 1d 3' 4.9" 
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 74%.
 
The mask-weighted lightcurve shows two main peaks.  The first starts at
T-60 sec, peaks at T+5 sec with a minimum at T+45 sec.  The second peaks
at T+65 sec and ends at T+135 sec.  T90 (15-350 keV) is 101 +- 5 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-20 to T+109.5 is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.71 +- 0.10.  The fluence in the 15-150 keV band is 2.5 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+70.22 sec in the 15-150 keV band
is 1.0 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence level.