TITLE: GCN CIRCULAR NUMBER: 39284 SUBJECT: Konus-Wind detection of GRB 250207A DATE: 25/02/11 13:50:11 GMT FROM: Anna Ridnaia at Ioffe Institute ridnaia@mail.ioffe.ru
A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
The long-duration GRB 250207A (Fermi-GBM detection: Fermi GBM team, GCN 39181; Swift-BAT detection: Ferro et al., GCN 39182; Moss et al., GCN 39245) was detected by Konus-Wind (KW) in the waiting mode.
A Bayesian block analysis of the KW waiting mode data reveals a >27 sigma count rate increase in the interval from T0-7.699 s to T0+15.853 s where T0 = T0(BAT) = 01:16:07.33 UT.
The KW light curve of this burst is available at http://www.ioffe.ru/LEA/GRBs/GRB250207A/
Modeling a time-integrated spectrum of the burst (from T0-7.699 s to T0+15.853 s) by a power law with exponential cutoff (CPL) model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep): yields alpha = -1.26 (-0.12, + 0.14) and Ep = 329(-64,+91) keV.
The total burst fluence is 1.04(-0.11,+0.13)x10^-5 erg/cm^2, and the 2.944 s peak energy flux, measured from T0+4.077 s, is 7.05(-0.98,+1.08)x10^-7 erg/cm^2. (both in the 20 keV - 10 MeV energy range).
All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary.
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