Max Tegmark's cosmology library: reion
Please click here to download the paper
described below.
Since this postscript file does not include the figures, I strongly
suggest that you download my
Ph.D. thesis
instead, in which this paper constitutes Chapter 3.
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here
if you are interested in
other research of mine.
ON THE INEVITABILITY OF REIONIZATION:
IMPLICATIONS FOR COSMIC MICROWAVE BACKGROUND FLUCTUATIONS
Authors:
Max Tegmark, Joe Silk & Alain Blanchard
Abstract:
Early photoionization of the intergalactic medium is discussed in a
nearly model-independent way, in order to
investigate whether early structures
corresponding to rare Gaussian peaks in a CDM model can
photoionize the intergalactic medium sufficiently
early to appreciably smooth out the microwave background fluctuations.
We conclude that this is indeed possible for a broad range
of CDM normalizations and is almost inevitable for unbiased CDM,
provided that the
bulk of these early structures are quite small, no more massive than about
10^8 M_{\odot}. Typical parameter values predict that reionization
occurs around z=50, thereby suppressing fluctuations on degree scales
while leaving the larger angular scales probed by COBE reasonably unaffected.
However, for non-standard CDM, incorporating mixed dark matter,
vacuum density or a tilted primordial power spectrum, early reionization
plays no significant role.
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