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I understand Leigh's response to three of the four
questions I asked, but I still do not understand why
photoionization is not a significant process.
In his discussion of ionization of intergalactic media
(IGM), Peebles (1993) states:
"The transitions to be considered are the radiative ones,
H + Y <-> p + e,
and electron collisions,
H + e -> p + e + e."
Only the recombination channel of the radiative transition
is common to both Leigh's analysis and Peebles (1993).
Peebles (1993) further states:
"If the temperature were well below 100 eV,
the dominant source of ionization could be
electromagnetic radiation."
Is Leigh's analysis limited to IGM in the deep gravity
wells of rich clusters? Is photoionization important
in most IGM, but not in IGM in rich clusters?
Daniel Crowe
Oklahoma School of Science and Mathematics
Ardmore Regional Center
dcrowe@sotc.org
Reference:
Peebles, P.J.E. (1993) Principles of Physical Cosmology.
Princeton, NJ: Princeton University Press, pp. 554-559.
I'm glad that someone else is following up on this one.
I have a conceptual conflict:
1) On a starry, night, looking to the Milky Way as
representative of the medium, that does indeed seem
an unpromising environment for energetic interaction.
2) I have the received factoid, that starlight represents
a temperature of several thousand degrees. While
probability of interactions may be low, they would
seem to have the requisite energy?