Cosmologies with a Synge gas and radiation
Abstract
The paper derives a relativistic equation of state in the context of the Friedmann cosmological models which allows a uniform and precise description of thermodynamics during expansion. The formalism permits a natural treatment of low photon/baryon ratios, considering the simplest case of nondegenerate protons, electrons, and blackbody radiation which shows that photon number is generally not conserved. A family of models is generated characterized by the total number of baryons within some fiducial radius, the curvature constant K, and the initial photon/baryon ratio. The results of computer calculations for low and high photon/baryon ratios are compared and their Jeans mass curves presented.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 December 1979
 DOI:
 10.1093/mnras/189.4.767
 Bibcode:
 1979MNRAS.189..767S
 Keywords:

 Astronomical Models;
 Baryons;
 Black Body Radiation;
 Cosmology;
 Equations Of State;
 Gas Expansion;
 Computerized Simulation;
 Electron Energy;
 Photons;
 Proton Energy;
 Relativistic Effects;
 Thermodynamic Equilibrium;
 Astrophysics