M. E. Prokhorov

Gravitational wave astronomy: In Anticipation of first sources to be detected

The first generation of long-baseline laser interferometric detectors of gravitational waves will start collecting data in 2001-2003. We carefully analyse their planned performance and compare it with the expected strengths of astrophysical sources. The scientific importance of the anticipated discovery of various gravitatinal wave signals and the reliability of theoretical predictions are taken into account in our analysis. We try to be conservative both in evaluating the theoretical uncertainties about a source and the prospects of its detection. After having considered many possible sources, we place our emphasis on (1) inspiraling binaries consisting of stellar mass black holes and (2) relic gravitational waves. We draw the conclusion that inspiraling binary black holes are likely to be detected first by the initial ground-based interferometers. We estimate that the initial interferometers will see 2-3 events per year from black hole binaries with component masses 10-15M_odot, with a signal-to-noise ratio of around 2-3, in each of a network of detectors consisting of GEO, VIRGO and the two LIGOs. It appears that other possible sources, including coalescing neutron stars, are unlikely to be detected by the initial instruments. We also argue that relic gravitational waves may be discovered by the space-based interferometers in the frequency interval 2x10^{-3}-10^{-2} Hz, at the signal-to-noise ratio level around 3.

Population synthesis in astrophysics

Population synthesis is a method for numerical simu- lation of the population of objects with a complex evolution. Thismethodiswidelyusedinastrophysics.Weconsideritsmain applications to studying astronomical objects. Examples of modeling evolution are given for populations of close binaries and isolated neutron stars. The application of the method to studying active galactic nuclei and the integral spectral char- acteristics of galaxies is briefly discussed. An extensive biblio- graphy on all the topics covered is provided.

Description of the “Scenario Machine”

We present an updated description of the “Scenario Machine” code, which is used to carry out population-synthesis analyzes of the evolution of close binary stars.

The LYRA-B Space Experiment: Goals and Principles for Its Realization

We describe goals and principles for the realization the Lyra-B space experiment onboard the International Space Station, which is currently being prepared at the Sternberg Astronomical Institute. The main goal of the experiment is to carry out a high-accuracy, multicolor all-sky survey of stars down to 16m–17m. The detailed structure of the expected observational data, their possible scientific use, and a number of technical problems are discussed.

Minimum star tracker specifications required to achieve a given attitude accuracy

We describe the principles of the computation of minimum specifications of the optical system and array detector of the star attitude sensor to achieve the required attitude accuracy for the given exposure. The computations assume that the attitude error is influenced only by random noise of diverse origin, whereas all systematic errors have been eliminated. We report the specifications required for trackers meant for different purposes. We show that the errors of existing star trackers exceed the lowest achievable error by one order of magnitude because of unaccounted biases. We discuss the types of these biases and the methods that can be used to take them into account or eliminate them.

Mechanical means for controlling the geometry of optical spacecraft attitude control systems and the necessary accuracy of these means

The accuracy of modern spacecraft attitude sensors has recently come to exceed the accuracy provided by the rigidity of the mechanical designs of spacecraft. One possible solution to this problem is to introduce additional sensors measuring the mutual orientation of the attitude sensors into the design of attitude control systems. In this paper we consider the questions of whether the simplest and most reliable mechanical distance measurement sensors can be used and whether their accuracy is sufficient for this purpose.

The necessity of introducing a geometric control subsystem into the composite attitude control systems of spacecraft and aircraft with modern precision

We propose to introduce a geometric control subsystem into the attitude control systems of space-craft that would allow the current system sensor configuration to be determined in real time.