Figure 2:
Schematic depicting the general
sequence of events in the post-recombination
Universe.
The solid and dotted lines
potentially track the Jeans mass of the average baryonic
gas component
from the recombination epoch
at
to the current time. A residual
ionization fraction
of
following recombination allows for
Compton interactions with photons to
, during which the Jeans mass
remains constant at
. The Jeans mass then
decreases as the Universe expands
adiabatically until the first collapsed structures form
sufficient
amounts of hydrogen molecules to
trigger a cooling instability and produce pop
III stars at
.
Star formation activity can then
reheat the Universe and raise the mean Jeans mass to
above
. This reheating could affect the
subsequent development of structures such as galaxies
and
the observed Ly
clouds.
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