Inverse Compton scattering in mildly relativistic plasma

We investigated the effect of inverse Compton scattering in mildly relativistic static and moving plasmas with low optical depth using Monte Carlo simulations, and calculated the Sunyaev-Zel'dovich effect in the cosmic background radiation. Our semi-analytic method is based on a separation of photon diffusion in frequency and real space. We use Monte Carlo simulation to derive the intensity and frequency of the scattered photons for a monochromatic incoming radiation. The outgoing spectrum is determined by integrating over the spectrum of the incoming radiation using the intensity to determine the correct weight. This method makes it possible to study the emerging radiation as a function of frequency and direction. As a first application we have studied the effects of finite optical depth and gas infall on the Sunyaev-Zel'dovich effect (not possible with the extended Kompaneets equation) and discuss the parameter range in which the Boltzmann equation and its expansions can be used. For high temperature clusters ($k_B T_e \gtrsim 15$ keV) relativistic corrections based on a fifth order expansion of the extended Kompaneets equation seriously underestimate the Sunyaev-Zel'dovich effect at high frequencies. The contribution from plasma infall is less important for reasonable velocities. We give a convenient analytical expression for the dependence of the cross-over frequency on temperature, optical depth, and gas infall speed. Optical depth effects are often more important than relativistic corrections, and should be taken into account for high-precision work, but are smaller than the typical kinematic effect from cluster radial velocities.Comment: LateX, 30 pages and 11 figures. Accepted for publication in the Astrophysical Journa

Identification of 8 INTEGRAL hard X-ray sources with Chandra

We report the results of identification of 8 hard X-ray sources discovered by the INTEGRAL observatory during the ongoing all-sky survey. These sources have been observed by Chandra. In 6 cases a bright X-ray source was found within the INTEGRAL localization region, which permitted to unambigously identify 5 of the objects with nearby galaxies, implying that they have an active galactic nucleus (AGN), whereas one source is likely an X-ray binary in LMC. 4 of the 5 newly discovered AGNs have measured redshifts in the range 0.025-0.055. The X-ray spectra reveal the presence of significant amounts of absorbing gas (NH in the range 10^22-10^24 cm^-2) in all 5 AGNs, demonstrating that INTEGRAL is starting to fill in the sample of nearby obscured AGNs.Comment: 4 pages, 2 figures, corrected Fig.

Development of strategic mechanisms for high-tech enterprises in the digital economy environment

The article is devoted to the development of conceptual provisions and recommendations for the development of strategic mechanisms for the work of high-tech enterprises in order to form an effective leadership strategy in the digital economy. The methodological basis of the study is based on the use of fundamental concepts, publications of modern specialists and scientists on the problems of digitalization. We used such scientific techniques and methods as: synthesis, comparative analysis, systemic and structural approach and method of expert assessments. The theoretical basis of the study was made up of scientific works of foreign and Russian scientists in the field of organizing strategic management, developing strategies and mechanisms for the development of enterprises operating in various sectors of the economy and conducting digital transformation. The process of client-oriented management is considered from the perspective of ecosystem development, which made it possible to form a set of rules for the effective construction and management of ecosystems. The author proposes a model of a roadmap necessary for developing a leadership strategy; the central element of the proposed map is a business model modified based on the synthesis of digital technologies