GRAVITATIONAL PHASE-TRANSITION OF FERMIONIC MATTER

We study the phase transition of a system of self-gravitating weakly i nteracting massive fermions in the presence of a large radiation-densi ty background in the framework of the Thomas-Fermi model. We show that by cooling a nondegenerate gas of weakly interacting massive fermions below some critical temperature, a condensed phase emerges, consistin g of quasidegenerate supermassive fermion stars. These compact dark ob jects could play an important role in structure formation in the early universe, as they might in fact provide seeds for galactic nuclei and quasistellar objects. (C) 1997 Elsevier Science B.V.