We study the inhomogeneous reionization in a critical density CDM universe
due to stellar sources, including Population III objects. The spatial
distribution of the sources is obtained from high resolution numerical N-body
simulations. We calculate the source properties taking into account a
self-consistent treatment of both radiative (ie ionizing and H2
-photodissociating photons) and stellar (ie SN explosions) feedbacks regulated
by massive stars. This allows us to describe the topology of the ionized and
dissociated regions at various cosmic epochs and derive the evolution of H, He,
and H2 filling factors, soft UV background, cosmic star formation rate and the
final fate of ionizing objects. The main results are: (i) galaxies reionize the
IGM by z~10 (with some uncertainty related to the gas clumping factor), whereas
H2 is completely dissociated already by z~25; (ii) reionization is mostly due
to the relatively massive objects which collapse via H line cooling, while
objects whose formation relies on H2 cooling alone are insufficient to this
aim; (iii) the diffuse soft UV background is the major source of radiative
feedback effects for z<15; at higher z direct flux from neighboring objects
dominates; (iv) the match of the calculated cosmic star formation history with
the one observed at lower redshifts suggests that the conversion efficiency of
baryons into stars is ~1%; (v) we find that a very large population of dark
objects which failed to form stars is present by z~8. We discuss and compare
our results with similar previous studies.Comment: 34 pages, emulateapj.sty, LaTeX, 13 figures. MNRAS, submitte
