Contemporary theories (SUSY GUT, Superstring/M-theory and others) not only predict the dependence of fundamental physical constants on energy ("running" constants), but also have cosmological solutions in which low-energy values of these constants vary with the cosmological time.
The predicted variations at the present epoch are small but non-zero, and they depend on theoretical model used. Clearly, a discovery of these variations would be a great step in our understanding of Nature. Even a reliable upper bound on a possible variation rate of a fundamental constant presents an effective tool for selecting viable theoretical models.
The main attention we pay to the following constants: the fine-structure constant and electron-to-proton mass ratio.
The primary objective of the study is the investigation of the physical properties and chemical composition of matter at different cosmological epochs. The investigation is based on high-resolution spectral observations of hydrogen and metal (C IV, Si IV, O VI and others) absorption-line profiles and advanced models of the radiative transfer in random media.
It is well known that primordial nucleosynthesis (Big Bang Nucleosynthesis, BBN) and cosmic microwave background radiation (CMBR) provide a unique window on the early Universe. They constitute two crucial quantitative tests of the standard big bang cosmological model. Indeed, BBN and CMBR, which have been related simbiotically from early works of the late 1940s, provide complementary views of the early Universe. The synthesis of the light elements is determined by events occuring in the epochs from ~1 to ~1000 s in the history of the Universe when temperatures varied from ~1010 K or higher to ~108 K. Thus, the observed abundances offer a probe of the Universe at epochs much earlier than those probed by CMBR (t~105 yr; T~104 K).
The study of the cosmic microwave background radiation (CMBR) was advanced especially over the last ten years. The observed CMBR spectrum may be fitted by the planck function at the temperature T=2.725±0.001 K with relative accuracy of 10-4. This means that radiation as well as the baryonic matter were under thermodynamical equilibrium at the begining of the epoch of the primordial plasma recombination. Nevertherless, the CMBR spectrum has to be a litlle distorted relative to the planck one. This distortion is a trace of different nonequilibrium processes which took place during the period of the recombination.
The nature of the active galactic nuclei (AGN) is one of the most important problems of the today astrophysics. By now the AGNs are usually thought to be supermassive black holes with masses of millions or even billions of solar masses. The high energy release is explained by accretion of the ambient matter onto their gravitational centers.
A model for H2O-maser source observed in the circumnuclear region of the acdtive galaxy NGC 4258 is developed. The maser emission of wavelenght 1.35 cm originates at distances of 0.15-0.30 pc from the center, in a thin molecular accretion disk (gas-dust torus) rotating around a supermassive black hole of mass about million solar masses.
The presented catalog contains a compilation of basic information on absorption-line systems in QSO spectra. The data are based on an extensive study of publications available to us up to December 2002. The lines presented here form 11,298 absorption systems.
The presented catalog contains a compilation of information on spectroscopic redshifts of distant galaxies. The data are taken from publications available to the authors up to June 2004. .
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