Can pregalactic objects generate galaxies?

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Abstract
In a hot universe with isothermal fluctuations or a tepid universe with general fluctuations, one would expect the first bound objects to be much smaller than galaxies. Various astrophysical processes associated with these objects could generate large-scale density fluctuations. For example, if they were asymmetric enough to form with large recoil velocities, they could generate statistical fluctuations on scales up to their traversal distance; if they formed in the radiation dominated era, there could be statistical fluctuations associated with the randomness in their initial distribution; if they were rare enough, they could act as condensation nuclei for larger regions; if they formed stars, they could induce large-scale fluctuations via shock fronts or ionization fronts. Thus the present structure on scales larger than the first bound regions, in particular, galaxies and clusters, need not derive directly from primordial fluctuations. The primordial fluctuations only have to produce relatively small objects.

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