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waynehu

Professor, Department of Astronomy and Astrophysics
University of Chicago

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CMB Introduction '96   Intermediate '01   Polarization Intro '01   Cosmic Symphony '04   Polarization Primer '97   Review '02   Power Animations   Lensing   Power Prehistory   Legacy Material '96   PhD Thesis '95 Baryon Acoustic Oscillations Cosmic Shear Clusters
Transfer Function WMAP Likelihood Reionization PPF for CAMB Halo Mass Conversion Cluster Abundance
Cosmology I [legacy 321] Cosmology II [321] Current Topics [282] Galaxies and Universe [242] Radiative Processes [305] Research Preparation [307] GR Perturbation Theory [408] CMB [448] Cosmic Acceleration [449]

Oscillitory Phase

Key Concepts

To better understand the formation of (angular) anisotropies from (spatial) inhomogeneities, let us start by reviewing the picture so far.

Photon pressure in a plane wave gravitational potential fluctuation causes a plane wave temperature variation across space that oscillates in time:

If we catch the oscillation at an extrema of the oscillation (blue-red phase) we see largish variations in the temperature across space.  On the other hand, if we catch it at the zero of the oscillation, we see no variation at all (maroon).   Since the frequency of the oscillations is directly proportional to the wavenumber (inverse length scale), there is a harmonic relationship between the wavenumbers that are caught at their extrema at any given time.  We'll focus on one of these modes.