The jeans problem for a thin galaxy in steady state
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Abstract
Given the potential, the equation of continuity and Poisson’s equation are solved for the variation perpendicular to the Galactic plane for a thin galaxy in a steady state. Simple expressions are obtained for the joint density function for the mass density and velocity, and for the distribution function for the velocity and its moments.
These results are applied using a potential suggested by Woolley and Stewart (1967) and Whitley (1977), which is Camm’s potential due to an isothermal gas stratified in parallel layers, plus the potential due to the Galactic centre. The resulting velocity distribution is quite close to the normal distribution usually assumed and cannot be distinguished from it by the data. The mass density distribution fits the log (relative density) curves better than the Camm solution, especially at large distances from the Galactic plane.
A formu1a, valid under conditions more genera1 than usual, is found for the total mass density in the neighbourhood of the Sun.
Key words
Jeans problem disk galaxies local mass densityPreview
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