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We present a preliminary analysis of spectral evolution of 35 long bright gamma-ray bursts (GRBs) detected by Konus-Wind instrument. From the temporal and spectral analyses of the sample, we investigate the evolution of parameters of the smoothly joined broken power-law spectral model (the Band “GRB” function), in particular, we analyse hardness-intensity correlation within a burst. We show that the bulk of bursts exhibit Ep ∝ F γ relation with the slope γ ∼ 0.3−0.5, where Ep is the vFv spectrum peak energy and F is the energy flux; while a number of events have the smooth initial phase with strong spectral evolution with γ ≳ 1. Finally, we discuss derived the Band function parameters and their evolution pattern in the framework of GRB emission models.

We present the analysis of duration and spectral-hardness distributions of ∼ 3000 gamma-ray bursts (GRBs) detected by Konus-Wind (KW) between November 1994 and early February 2019. We analyse burst T 50 and T 90 durations (the time intervals which contain the central 50% to 90% of the total burst count fluence, respectively) and argue that T 50 is more robust duration measure than T 90. Using a two log-normal component fit to the T 50 distribution we pick the boundary between the overlapping classes of short-duration and long-duration bursts to be at T 50 = 0.7 s, which implies the fraction of short GRBs (T 50 < 0.7 s) to be ∼ 17%. Using Gaussian mixture model fits we show that hardness-duration distribution can be well described by three Gaussian components, with two components corresponding to short/hard and long/soft GRB population, and the third component covering the softest GRBs with intermediate durations. This classification suggests that ∼ 14% KW GRBs are from short/hard population. Finally we discuss a possibility to discriminate between physically distinct Type I and Type II GRBs with the help of hardness-duration distribution.

We present Konus-UF and Helicon-I, the future space-based experiments designed to study temporal and spectral characteristics of gamma-ray bursts, solar flares, soft gamma-repeater bursts, and other transient phenomena over a wide energy range from 10 keV to 15 MeV. The instruments will be mounted onboard the World Space Observatory–Ultraviolet (WSO-UV) and the InterhelioProbe spacecraft, respectively. The spacecraft orbits are going to be far from the Earth’s magnetosphere, which enables nearly uninterrupted observations of the entire sky under stable background conditions.

Although half a century has passed since the discovery of Gamma-ray bursts (GRBs), there is no evidence for any strongly lensed event. Using GRB luminosity function and GRB formation rate estimates for the Konus-Wind burst sample with known redshifts, and a Singular Isothermal Sphere as a gravitational lens model, we predict the detection rate of both GRB images being ≈ 0.02–0.05 events per year. The result is consistent with the non-detection of lensed bursts in the KW triggered GRB sample.