1) Speaker: N.R. Ikhsanov (Pulkovo Observatory)
Title: “The origin of ejecting white dwarf in AR Sco system”
Abstract: see Russian version
2) Speaker: E.P. Kurbatov (INASAN)
Title: “On the possible electromagnetic manifestations of merging black holes”
Abstract: The scenario of merging two black holes surrounded by an accretion disk is considered. As a result of radiation of gravitational waves, the mass of the central object decreases, and the accretion disk experiences perturbation. The main consequence of this disturbance is the formation of a shock wave propagating from the center to the periphery of the disk. It is shown that if the mass of the merging double is 55 Msun (as in the case of the event GW170814), then a flare from the shock wave will cause the bolometric luminosity of the disk to grow by 4-6 orders of magnitude, to 10^45 erg/s (absolute magnitude -23.8m). Taking into account the distance to the source, 540 Mpc, and reasonable assumptions on the parameters of the accretion disk, it appears that the apparent magnitude of the flare, at the maximum of the spectral flux density, should be 12.8-14.2m, and the duration of the flash is a few minutes. The most of radiation flux from the shock wave lies in the X-ray and gamma bands. It can be observed with the EPIC instrument of the XMM-Newton observatory, or the telescope eROSITA of the Spectrum-RG observatory, or the IBIS instrument of the INTEGRAL observatory.