Dynamic Screening and Thermonuclear Reaction Rates

We show that there are no dynamic screening corrections to the Salpeter's enhancement factor in the weak-screening limit.Comment: 7 pages LaTex, no figures, Submitted to Ap

Effects of Rotation and Relativistic Charge Flow on Pulsar Magnetospheric Structure

We propose an analytical 3-D model of the open field-line region of a neutron star (NS) magnetosphere. We construct an explicit analytic solution for arbitrary obliquity (angle between the rotation and magnetic axes) incorporating the effects of magnetospheric rotation, relativistic flow of charges (e.g. primary electron beam) along the open field lines, and E X B drift of these charges. Our solution employs the space-charge-limited longitudinal current calculated in the electrodynamic model of Muslimov & Tsygan (1992) and is valid up to very high altitudes nearly approaching the light cylinder. We assume that in the innermost magnetosphere, the NS magnetic field can be well represented by a static magnetic dipole configuration. At high altitudes the open magnetic field lines significantly deviate from those of a static dipole and tend to focus into a cylindrical bundle, swept back in the direction opposite to the rotation, and also bent towards the rotational equator. We briefly discuss some implications of our study to spin-powered pulsars.Comment: 24 pages, 3 figures, accepted for publication in Ap

Career Self-Guidance as a Key Factor in the Development of High School Students’ Competitive Ability and Orientedness

Introduction. The article discusses the relationship between career self-guidance of high school students and their competitiveness. The authors highlight the indicators of career self-guidance and analyze their influence on the actualization of socially significant qualities, promoting the development of adolescent competitiveness. Influence of information technologies changes radically content and structure of professional activities. The ability to respond to the changes in the labor market and integrate into the relations while carrying out professional activity is essential for young people. The purpose of this article is to consider the specifics of career self-guidance of contemporary senior pupils and to analyze its influence on the competitive orientation of pupils. Materials and Methods. A questionnaire survey of high school students was selected for its reliability and validity in studying competitive skills. IBM SPSS Statistics 23 software was used to process and analyze the obtained data (N = 1 067 respondents). Results. The results reveal that the career self-guidance of high school students is a key factor in the process of formation of their competitive orientation. The main motives of future professional activity of senior students and the criteria of educational institution choice were defined. In addition, the key factors that influence the process of making decision of education continuing and their connection with competitive oriented pupils were considered. The indicators of career self-guidance process were revealed. Discussion and Conclusion. The research results may be useful for teachers and psychologists at high schools, for representatives who study competitive relations in educational sphere and for educators at vocational institutions and universities to develop career guidance strategies. These findings provide the following insights for future research: a comparative analysis of senior pupils’ career guidance measures` efficiency, conducted by different structures, the study of Internet technologies impact on career self-guidance and the study of atlases and new occupations list and their position in a future labor market

Soliton in Gravitating Gas. Hoag's Object

We explore the possibility of creating of solitons in gravitating gas. It is shown that the virial arguments does not put an obstacle for the existence of localized static solutions. The simplest toroidal soliton of gravitating gas could be the explanation of the peculiar galaxy named Hoag's object.Comment: 14 pages, 1 Figur

Physics of the Merging Clusters Cygnus A, A3667, and A2065

We present ASCA gas temperature maps of the nearby merging galaxy clusters Cygnus A, A3667, and A2065. Cygnus A appears to have a particularly simple merger geometry that allows an estimate of the subcluster collision velocity from the observed temperature variations. We estimate it to be ~2000 km/s. Interestingly, this is similar to the free-fall velocity that the two Cygnus A subclusters should have achieved at the observed separation, suggesting that merger has been effective in dissipating the kinetic energy of gas halos into thermal energy, without channeling its major fraction elsewhere (e.g., into turbulence). In A3667, we may be observing a spatial lag between the shock front seen in the X-ray image and the corresponding rise of the electron temperature. A lag of the order of hundreds of kiloparsecs is possible due to the combination of thermal conduction and a finite electron-ion equilibration time. Forthcoming better spatial resolution data will allow a direct measurement of these phenomena using such lags. A2065 has gas density peaks coincident with two central galaxies. A merger with the collision velocity estimated from the temperature map should have swept away such peaks if the subcluster total mass distributions had flat cores in the centers. The fact that the peaks have survived (or quickly reemerged) suggests that the gravitational potential also is strongly peaked. Finally, the observed specific entropy variations in A3667 and Cygnus A indicate that energy injection from a single major merger may be of the order of the full thermal energy of the gas. We hope that these order of magnitude estimates will encourage further work on hydrodynamic simulations, as well as more quantitative representation of the simulation results.Comment: Corrected the Cyg-A figure (errors shown were 1-sigma not 90%); text unchanged. ApJ in press. Latex, 5 pages, 3 figures (2 color), uses emulateapj.st