TITLE:   GCN CIRCULAR
NUMBER:  27922
SUBJECT: Konus-Wind observation of ultra-long GRB 200612A
DATE:    20/06/12 20:13:01 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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

The ultra-long GRB 200612A
(Swift-BAT detection Sonbas et al., GCN 27915;
MASTER OT detection: Lipunov et al., GCN 27917)
was detected by Konus-Wind in the waiting mode.

The burst light curve shows four emission episodes
in the interval from ~T0(BAT) s to ~T0(BAT)+1020 s.

The K-W light curve of this burst is available at
http://www.ioffe.ru/LEA/GRBs/GRB200612A/

As observed by Konus-Wind, the burst had a fluence of
4.08(-0.34,+1.04)x10^-5 erg/cm2 and a 2.944-s peak flux,
measured from ~T0(BAT)+478.8 s, of 2.75(-0.62,+0.85)x10^-7 erg/cm2/s
(both in the 20 - 1500 keV energy band).

The K-W 3-channel time-integrated spectrum
(from ~T0(BAT) s to ~T0(BAT)+1020 s)
is well described by a cutoff power-law model
with alpha = -1.0(-0.2,+0.3) and Ep= 253(-65,+95) keV.

All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.