Constraints on injection parameters of cosmic rays in the Galactic center from resolved HESS observations

In this study, we investigate how restrictive the γ-ray emission from the Galactic center region, as seen by HESS and other Cherenkov air shower arrays, is against various models for cosmic ray injection. We derive diffusion coefficients which fit the observed spatial scales of diffuse γ-ray emission from the extended emission associated with the molecular clouds SgrA, B and C. Using these diffusion coefficients, we then obtain a limit for time scale of assumed recent proton acceleration near the SMBH, as the spatial size of SgrA^∗ in VHE γ-rays has to be consistent with the observed unresolved HESS point source size at this position. The signal from this hadronic component may be mixed with the expected VHE inverse Compton emission from the nearby unresolved pulsar wind nebula.     

Attempt to identify a source mechanism of Mercury’s sodium exosphere by a spectrometer using Fabry–Perot etalon

The Mercury’s Sodium Atmosphere Spectral Imager (MSASI) on BepiColombo (BC) will address a range of fundamental scientific questions pertaining to Mercury’s exosphere. The measurements will provide new information on regolith–exosphere–magnetosphere coupling as well as new understanding of the dynamics governing the exosphere bounded by the planetary surface, the solar wind and interplanetary space. MSASI is a high-dispersion visible spectrometer working in the spectral range around sodium D2 emission (589 nm). A tandem Fabry–Perot etalon is used to achieve a compact design. We presents a design of the spectral analyzer using Fabry–Perot interferometer. We conclude that: (1) The MSASI optical design is practical and can be implemented without new or critical technology developments; (2) The thermally-tuned etalon design is based on concepts, designs and materials that have good space heritage.     

Structure of technological-purpose automation models by the example of a computer-aided design system of labor standards

Structures of models for computer-aided calculation of cutting conditions and time standards for the NORMA computer-aided design system of labor standards (CADS LS) are described.     

Intermittency of solar wind density fluctuations and its relation to sharp density changes

The paper presents the study of turbulent properties of the solar wind plasma, namely, the intermittency of fluctuations of the solar wind ion flux in the earlier unexplored region of comparatively high frequencies (0.01–1 Hz). Special attention is given to a comparison of intermittency for solar wind observation intervals containing sharp (shorter than 10 min) and high-amplitude (greater than 20%) changes of the ion flux to intervals without such changes. The solar wind observation intervals containing sharp changes of the flux are found to be essentially more intermittent than the intervals of quiet solar wind. Such a comparison allows one to reveal the fundamental difference in turbulent properties of the solar wind depending on the presence or absence of sharp boundaries in plasma structures.     

High energy radiation from the direction of the galactic black hole Sgr A

X-ray observations indicate that the Galactic black hole Sgr A^∗ is inactive now, however, we suggest that Sgr A^∗ can become active when a captured star is tidally disrupted and matter is accreted into the black hole. Consequently the Galactic black hole could be a powerful source of relativistic protons with a characteristic energy ∼10⁵² erg per capture. The diffuse GeV and TeV γ-rays emitted in the direction of the Galactic Center (GC) are the direct consequences of p–p collisions of such relativistic protons ejected by very recent capture events occurred ?10⁵ yr ago. On the other hand, the extended electron-positron annihilation line emission observed from GC is a phenomenon related to a large population of thermalized positrons, which are produced, cooled down and accumulated through hundreds of past capture events during a period of ∼10⁷ yr. In addition to explaining GeV, TeV and 511 keV annihilation emissions we also estimate the photon flux of several MeV resulting from in-flight annihilation process.     

Influence of ultrasonic machining on physico-mechanical properties of adhesive joints and epoxide compounds

The results of experimental studies concerning the physico-mechanical properties of adhesive joints and epoxide compound-based coatings after ultrasonic machining are presented. Also considered is a change of adhesive strength and residual stresses in different “metal — polymer” systems.     

A concept of a spacecraft with small initial mass placed in the near-earth orbit by a laser rocket engine

A method and results of calculating the laser radiation power values necessary to place an artificial earth satellite in orbit are presented; the values depend on the initial vehicle mass, velocity of the working fluid efflux from the laser rocket engine nozzle, velocity of vehicle motion, optimal values of thrust-to-weight ratio taking into account irreversible energy losses in the rocket engine jet. The possibility of creating a spacecraft with small initial mass is substantiated. A layout scheme of the propulsive system is proposed that makes it possible to divide total laser radiation power and to use atmospheric air as a working fluid.     

Recent studies of the optical counterpart of GX 1+4

The galactic X-ray source GX 1+4 has been undergoing remarkable changes since early 1991. The X-ray pulsar has shown fast spin down accompanied by an increase in the hard X-ray intensity. We have obtained 1.6Å resolution spectra of the optical counterpart extending the known spectrum to 8500Å. The Ca II (8498Å) line seen for the first time from this source is indicative of a nova burst scenario. Other lines detected for the first time are detailed and the significance of these features is discussed.     

Fluxes of low-energy particles in quiet periods of solar activity and the <Emphasis Type="Italic">MgII</Emphasis> index

Low fluxes of protons with energies 0.3–10 MeV were studied during 21–23 solar cycles as a function of the MgII index using the data of the instruments CPME, EIS (IMP8), and EPHIN (SOHO). It has been shown that a) during quiet time of solar activity the fluxes of protons (background protons) have a positive correlation with the MgII index value throughout the solar cycle, b) specific features of variations of the MgII index during the solar minima of 1986–1987 and 1996–1997 can be considered, as well as variations of background fluxes of low energy charged particles, to be manifestations of the 22-year magnetic cycle of the Sun, and c) periods of the lowest value of the MgII index are also characterized by the smaller values of the ratio of intensities of protons and helium nuclei than in other quiet periods. A hypothesis is put forward that acceleration in a multitude of weak solar flares is one of the sources of background fluxes of low energy particles in the interplanetary space.     

Control of complex nonlinear vibrations of sandwich beams

Complex vibrations of the Bernoulli-Euler sandwich beams are considered. The solution is performed by the numerical methods of finite elements in the Bubnov-Galerkin form and finite differences of the second order of accuracy. The approaches for control of chaotic vibrations in the Bernoulli-Euler sandwich beams are proposed.