[vsnet-grb-info 26761] Konus-Wind detection of GRB 201105A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28864
SUBJECT: Konus-Wind detection of GRB 201105A
DATE:    20/11/07 16:14:54 GMT
FROM:    Anna Ridnaia at Ioffe Institute  <ridnaia at mail.ioffe.ru>

A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 201105A
(Fermi-GBM detection: Biltzinger et al., GCN Circ. 28842,
Bissaldi & Lesage, GCN Circ. 28843;
Swift-BAT trigger #1004239: Markwardt et al., GCN Circ. 28845)
triggered Konus-Wind at T0=19865.464 s UT (05:31:05.464).

The burst light curve shows a single FRED-like pulse
which starts at ~T0-2.4 s and has a total duration of ~29.6 s.
The emission is seen up to ~4 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB201105_T19865/

As observed by Konus-Wind, the burst
had a fluence of 7.88(-0.85,+0.79)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+2.624 s,
of 1.59(-0.30,+0.30)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+26.368 s)
is best fit in the 20 keV - 4 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.55(-0.12,+0.13),
the high energy photon index beta = -2.11(-0.17,+0.11),
the peak energy Ep = 286(-31,+42) keV
(chi2 = 92/71 dof).

The spectrum near the maximum count rate
(measured from T0+2.304 to T0+4.096 s)
is best fit in the 20 keV - 4 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.43(-0.18,+0.20),
the high energy photon index beta = -2.05(-0.18,+0.12),
the peak energy Ep = 305(-48,+66) keV
(chi2 = 51/60 dof).

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