On the universal X-ray luminosity function of binary X-ray sources in galaxies

The empirically determined universal power-law shape of X-ray luminosity function of high mass X-ray binaries in galaxies is explained by fundamental mass-luminosity and mass-radius relations for massive stars.Comment: 4 pages, plain LaTeX, no figures. Submitted to Astronomy Letter

Population synthesis of gamma-ray bursts with precursor activity and the spinar paradigm

We study statistical properties of long gamma-ray bursts (GRBs) produced by the collapsing cores of WR stars in binary systems. Fast rotation of the cores enables a two-stage collapse scenario, implying the formation of a spinar-like object. A burst produced by such a collapse consists of two pulses, whose energy budget is enough to explain observed GRBs. We calculate models of spinar evolution using results from a population synthesis of binary systems (done by the `Scenario Machine') as initial parameters for the rotating massive cores. Among the resulting bursts, events with the weaker first peak, namely, precursor, are identified, and the precursor-to-main-pulse time separations fully agree with the range of the observed values. The calculated fraction of long GRBs with precursor (about 10 per cent of the total number of long GRBs) and the durations of the main pulses are also consistent with observations. Precursors with lead times greater by up to one order of magnitude than those observed so far are expected to be about twice less numerous. Independently of a GRB model assumed, we predict the existence of precursors that arrive up to >~ 10^3 s in advance of the main events of GRBs.Comment: 11 pages, 9 figures; published versio

Merging of Components in Close Binaries: Type Ia Supernovae, Massive White Dwarfs, and Ap stars

The "Scenario Machine" (a computer code designed for studies of the evolution of close binaries) was used to carry out a population synthesis for a wide range of merging astrophysical objects: main-sequence stars with main-sequence stars; white dwarfs with white dwarfs, neutron stars, and black holes; neutron stars with neutron stars and black holes; and black holes with black holes.We calculate the rates of such events, and plot the mass distributions for merging white dwarfs and main-sequence stars. It is shown that Type Ia supernovae can be used as standard candles only after approximately one billion years of evolution of galaxies. In the course of this evolution, the average energy of Type Ia supernovae should decrease by roughly 10%; the maximum and minimum energies of Type Ia supernovae may differ by no less than by a factor of 1.5. This circumstance should be taken into account in estimations of parameters of acceleration of the Universe. According to theoretical estimates, the most massive - as a rule, magnetic - white dwarfs probably originate from mergers of white dwarfs of lower mass. At least some magnetic Ap and Bp stars may form in mergers of low-mass main sequence stars (<1.5 mass of the Sun) with convective envelopes.Comment: 15 pages, 4 figure

СЕТЕВАЯ МОДЕЛЬ И АЛГОРИТМ РЕШЕНИЯ ЗАДАЧИ ОПТИМАЛЬНОГО РАСПРЕДЕЛЕНИЯ ТЕПЛОВЫХ НАГРУЗОК МЕЖДУ ТЕПЛОИСТОЧНИКАМИ ПРЕДПРИЯТИЯ ТЕПЛОВЫХ СЕТЕЙ

The paper  presents an algorithm for optimization of thermal load distribution among heat-sources in the system of centralized heat supply. The algorithm can be used while elaborating plans for development of heat supply systems in cities and settlements.Представлен алгоритм для оптимизации распределения тепловых нагрузок между теплоисточниками в системе централизованного теплоснабжения. Алгоритм может быть использован при разработке планов развития систем теплоснабжения городов и населенных пунктов

Magnetars, Gamma-ray Bursts, and Very Close Binaries

We consider the possible existence of a common channel of evolution of binary systems, which results in a gamma-ray burst during the formation of a black hole or the birth of a magnetar during the formation of a neutron star. We assume that the rapid rotation of the core of a collapsing star can be explained by tidal synchronization in a very close binary. The calculated rate of formation of rapidly rotating neutron stars is qualitatively consistent with estimates of the formation rate of magnetars. However, our analysis of the binarity of newly-born compact objects with short rotational periods indicates that the fraction of binaries among them substantially exceeds the observational estimates. To bring this fraction into agreement with the statistics for magnetars, the additional velocity acquired by a magnetar during its formation must be primarily perpendicular to the orbital plane before the supernova explosion, and be large.Comment: 16 pages, 4 figure

AE Aquarii represents a new subclass of Cataclysmic Variables

We analyze properties of the unique nova-like star AE Aquarii identified with a close binary system containing a red dwarf and a very fast rotating magnetized white dwarf. It cannot be assigned to any of the three commonly adopted sub-classes of Cataclysmic Variables: Polars, Intermediate Polars, and Accreting non-magnetized White Dwarfs. Our study has shown that the white dwarf in AE Aqr is in the ejector state and its dipole magnetic moment is $\mu ~ 1.5 \times 10^{34} G cm^3$. It switched into this state due to intensive mass exchange between the system components during a previous epoch. A high rate of disk accretion onto the white dwarf surface resulted in temporary screening of its magnetic field and spin-up of the white dwarf to its present spin period. Transition of the white dwarf to the ejector state had occurred at a final stage of the spin-up epoch as its magnetic field emerged from the accreted plasma due to diffusion. In the frame of this scenario AE Aqr represents a missing link in the chain of Polars evolution and the white dwarf resembles a recycled pulsar.Comment: accepted for publication in Astronomy Reports (July 2012

Консорциум научных библиотек Европы 2008: новые задачи

On the activities of one of the most significant international organizations connected with research of book history - Consortium of European Research Libraries. The creation of a bibliographic database of the printed book from 1452 to 1830, which was supposed to collect materials from libraries of Europe, was the goal of Consortium since the beginning of its foundation. The authors of the article write that today the activities of the Consortium is much broader, it turns into international research institute on the history of culture.О деятельности одной из наиболее значительных международных организаций, связанных с исследованием истории книги — Консорциума европейских научных библиотек. С начала основания Консорциума его задачей являлось создание библиографической базы данных печатной книги с 1452 г. по 1830 г., в которой предполагалось собрать материалы из библиотек Европы. Сегодня сфера деятельности Консорциума стала значительно шире, он превращается в международную исследовательскую организацию по истории культуры, об этом и рассказывают авторы статьи