arXiv subjects

Alexander B. Kashuba

Publications and source records attributed to Alexander B. Kashuba.

3 recordsLinked to original sources

arXiv2018

Galaxies as fluctuations in cosmic stellar liquid

Large self-gravitating stellar systems share with correlated liquids in condensed matter physics a pattern of hierarchical density variations. While it takes the microscopic time resolution to discern the correlated dynamics of the critical opalescence, characteristic astronomical times hide fluctuational dynamics of stellar liquids, where, governed by interstellar correlations, denser clusters of stars assemble and disperse. For a semi-isolated galaxy, these dynamical fluctuations are dense globular clusters. For a galaxy cluster, these dynamical fluctuations are the member galaxies, elliptical ones in the interior. Bright over-density fluctuations, galaxies, are exhibits of only a small fraction of stars found in a cosmic stellar liquid, the dark matter. Here I report a fluctuational gravitational collapse as a property of a self-gravitating system in the virial equilibrium.

astro-ph.GA↗

arXiv2017

Relativistic self-gravitating gas in dynamical equilibrium

Static spherically symmetric solution of the Einstein's equations is found representing averaged properties of an infinite self-gravitating gas in the dynamical equilibrium. It depends upon three parameters: the core radius, the relativistic factor $0<z<1$, defining the density and the mass, and one structural parameter. In the relativistic limit, $z\to 1$, an open nucleus of focused gravitational fields develops with the size being a small fraction of the core radius whereas the outskirts of the self-gravitating gas remains non-relativistic. Inside the nucleus the self-gravitating gas is described by a universal perfect fluid with the relativistic one-dimensional equation of state. At $z=1$, the space and time develops a point like singularity at the center. A characteristic property of the nucleus is incompressibility. New particles added to the self-gravitating gas bounce back into the outskirts rather than fall into the center.

physics.gen-ph↗

arXiv2017

Statistical mechanics of gravitating gas like galaxy

The most probable state of an infinite self-gravitating gas in the dynamical equilibrium is defined by `gravitational haziness', a parameter representing many-body effects and formally like the temperature in the case of thermal equilibrium. A kinetic equation is constructed using a concept of statistical equipartition of the virial among subsystems of the self-gravitating gas. A closed equation for the gravitational potential is conjectured as a special property of the kinetic equation. An equilibrium particle distribution function in the phase space, an analog of the Maxwell-Boltzmann weight, and a galaxy equation of state are found for all `gravitational haziness'. The first law of a `hazydynamics' (thermodynamics) states that the total mass of an astronomical stellar collection is the sum of the Archimedes displaced mass and an excess `gobbled' mass determined by the `gravitational haziness' and history.

astro-ph.GA↗