GCN Circular 6230

Subject

Konus-Wind observation of GRB 070328

Event

Date

2007-03-29T14:06:43Z (19 years ago)

From

Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and
T. Cline on behalf of the Konus-Wind team report:

The long GRB 070328 (Swift-BAT trigger #272773:
Markwardt et al., GCN 6224Loading...
 
 ; Stamatikos et al., GCN 6225Loading...
 
 ),
triggered Konus-Wind at T0=14029.993 s UT (03:53:49.993).

The Konus-Wind light curve shows multipeaked structure
with a duration of ~45 s, followed by a weak tail
marginally seen up to T-T0~130 s in the 70-300 keV band.
As observed by Konus-Wind the burst
had a fluence of 5.95(-0.76, +1.06)x10^-5 erg/cm2,
and the 256-ms peak flux measured from T0+1.808 s
4.57(-0.91, +1.07)x10^-6 erg/cm2/s
(both in the 20 keV - 6 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+41.216 s) is well fitted (in the 20 keV - 6 MeV range)
by GRBM (Band) model for which:
the low-energy photon index is alpha = -0.99(-0.11, +0.13),
the high energy photon index beta = -1.99(-0.40, +0.18),
the peak energy Ep = 496(-117, +172) keV (chi2 = 80/77 dof).
Fitting by a power law with exponential cutoff model:
dN/dE ~ E^(-alpha) * exp(-(2-alpha)*E/Ep)
yields alpha = 1.09 +/- 0.08,
and Ep = 688(-119, +173) keV (chi2 = 88/78 dof).

All the quoted errors are at the 90% confidence level.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.rssi.ru/LEA/GRBs/GRB070328_T14029/