Max Tegmark's library:

Figure 8. The origin of "Doppler peaks": why density and velocity oscillations do not cancel. Reprinted from Hu (1995).

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Doppler peaks and all that:
CMB anisotropies and what they can tell us


Max Tegmark


The power spectrum of fluctuations in the cosmic microwave background (CMB) depends on most of the key cosmological parameters. Accurate future measurements of this power spectrum might therefore allow us to determine h, Omega, Omega_b, Lambda, n, T/S, etc, with hitherto unprecedented accuracy. In these lecture notes, which are intended to be readable without much prior CMB knowledge, we review the various physical processes that generate CMB fluctuations, focusing on how changes in the parameters alters the shape of the power spectrum. We also discuss foregrounds and real-world data analysis issues and how these affect the accuracy with which the parameters can be measured.

Online references:

This site also contains the latest versions of some papers that are referenced in the text; Haehnelt & Tegmark 1995, Tegmark 1995, Tegmark & Bunn 1995, Tegmark & Efstathiou 1995 and Tegmark & Silk 1995.

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This page was last modified July 1, 1998.