Konus-Wind detection of GRB 210318B

The long-duration GRB 210318B (Swift-BAT detection: Troja et al., GCN Circ. 29663) triggered Konus-Wind at T0=11309.57 s UT (03:08:29.570). The burst light curve shows a multipeaked structure which starts at ~T0-0.5 s and has a total duration of ~14 s. The emission is seen up to ~3 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB210318_T11309/ As observed by Konus-Wind, the burst had a fluence of 3.83(-0.44,+0.50)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+1.872 s, of 1.57(-0.28,+0.29)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+13.824 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.81(-0.12,+0.15), the high energy photon index beta = -2.51(-0.39,+0.23), the peak energy Ep = 264(-32,+33) keV (chi2 = 70/82 dof). The spectrum near the maximum count rate (measured from T0+0.256 to T0+5.632 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.64(-0.13,+0.14), the high energy photon index beta = -2.59(-0.45,+0.23), the peak energy Ep = 297(-32,+36) keV (chi2 = 67/81 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.