On the formation of elliptical galaxies*

Abstract

It is suggested that elliptical galaxies are formed in an expansion from a steady-state situation in which the mean density is of order 10 -8 g/cm 3 . Such an expansion is possible because the inhomogeneous steady-state theory has an instability in which the creation process is essentially cut-off, and in which expansion proceeds according to the Einstein-de Sitter law. The characteristic mass of the ‘observable universe at the onset of such an instability is ca . 1013M®, and this is taken to set the upper limit to the masses of galaxies.