GCN Circular 6290
Subject
GRB 070412, Swift-BAT refined analysis
Date
2007-04-12T13:39:26Z (17 years ago)
From
Hans Krimm at NASA-GSFC <krimm@milkyway.gsfc.nasa.gov>
T. Sakamoto (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), P. Romano (Univ. Bicocca & INAF-OAB),
G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC)
on behalf of the Swift-BAT team:
Using the data set from T-239.3 to T+962.8 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 070412
(trigger #275119) (Romano, et al., GCN Circ. 6273). The BAT
ground-calculated position is RA, Dec = 181.525, 40.133 deg which is
RA(J2000) = 12h 06m 6.1s
Dec(J2000) = 40d 07' 57.0"
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 98%.
The mask-weighted light curve shows a double-peaked structure
with the first peak from approximately T-4 sec to T+10 sec and
a second 2-sec long peak at T+30 sec. T90 (15-350 keV) is
34 +- 2 sec (estimated error including systematics). The spacecraft
slewed away from the burst location at T+122 sec, although the burst
remained in the partially coded field of view until T+716 sec,
when the spacecraft slewed away again.
The time-averaged spectrum from T-4.1 to T+31.2 is best fit by
a simple power-law model. The power law index of the time-averaged
spectrum is 1.45 +- 0.20. The fluence in the 15-150 keV band is
4.8 +- 0.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured
from T+5.32 sec in the 15-150 keV band is 0.7 +- 0.1 ph/cm2/sec.
All the quoted errors are at the 90% confidence level.