Showing papers on "Structure formation published in 1970"

On the Non-Linear Effect of Cosmic Fluid in an Expanding Universe

Abstract: In order to clarify the process of galaxy formation, basic equations for dealing with various non-linear effects of cosmic fluid, such as the interaction between eddy motions and shearing ones and the non-linear character of gravity for the promotion of density contrast, are derived from our Newtonian hydrodynamical equations in an expanding universe, which are suitable after the decoupling time of matter from the primordial radiation. The equations are localized by means of power series expansion of relevant quantities in the neighborhood of an equilibrium point in the fluid and solved in several cases. As a result, it is shown that, if a suitable rotation specified by a parameter e such as 1>e20 exists, the rotating body becomes a gravi­ tationally bound system at an instant when the density ratio to the background reaches the value (3n/ 4)2 {2/ (1 +e) }3. Basic equations for dealing with Ozernoi and Chernin's mechanism for hydrodynamical instability before the decoupling time are also derived in a tentative manner.