GCN Circular 6237
Subject
GRB 070330, Swift-BAT refined analysis
Date
2007-03-31T20:25:03Z (18 years ago)
From
Craig Markwardt at NASA/GSFC/UMD <craigm@milkyway.gsfc.nasa.gov>
E. Fenimore (LANL), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), N. Gehrels (GSFC), D. Grupe (PSU),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), 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-240 to T+963 sec from the full telemetry
downlink, we report further analysis of BAT GRB 070330 (trigger
#273180) (Grupe et al., GCN Circ. 6232). The BAT ground-calculated
position is RA, Dec = 269.533, -63.799 deg which is
RA(J2000) = 17h 58m 7.9s
Dec(J2000) = -63d 47' 54.7"
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90%
containment). The partial coding was 80%.
The mask weighted light curve consists of a single FRED-like peak.
T90 (15-350 keV) is 9.0 +- 1 sec (estimated error including
systematics).
The time-averaged spectrum from T-1.1 to T+8.9 is best fit by a power
law with an exponential cutoff. This fit gives a photon index
-0.33 +- 1.76, and Epeak of 36.3 +- 6.1 keV (chi squared 56.05 for 56
d.o.f.). For this model the total fluence in the 15-150 keV band is
1.8 +- 0.3 x 10^-07 erg/cm2 and the 1-sec peak flux measured from
T-0.06 sec in the 15-150 keV band is 0.9 +- 0.1 ph/cm2/sec. A fit to
a simple power law gives a photon index of 2.06 +- 0.22 (chi squared
66.7 for 57 d.o.f.). All the quoted errors are at the 90% confidence
level.