C_l Movies

In each movie we plot the angular power spectrum, which is l(l+1)C_l versus log(l). Here l is the multipole moment, which is the variable conjugate to angle. The x-axis tick marks are at l=10,100,1000 and the y-axis tick marks are at l(l+1)C_l =2, 4, 6, 8,...

Reionization (40K)

A scenario in which recombination proceeds as usual, except that the universe becomes totally reionized at some redshift z, less than a few hundred. We show the angular power spectrum change with the optical depth tau integrated from z=0 to high redshift. The optical depth changes (linearly) from 0 to 2, shown as the horizontal line at the top of the plot increasing rightwards.

Baryon fraction (50K)

We show the angular power spectrum change with the baryon fraction. The hubble constant is held fixed at 50km/s/Mpc while Omega Baryon changes (linearly) from 1% to 10% (shown as the horizontal line at the top of the plot increasing rightwards).

Lambda (60K)

We show the angular power spectrum change with increasing Lambda. All other parameters are held fixed at their sCDM values and Lambda is increased from 0 to 0.9 (shown as the horizontal line at the top of the plot increasing rightwards). Note that the physical interpretation of this movie is somewhat confused by our simple choice of normalization at l=2.

Hubble Constant (60K)

We show the angular power spectrum change with increasing Hubble constant. All other parameters are held fixed at their sCDM values and h is increased from 0.35 to 0.7 (shown as the horizontal line at the top of the plot increasing rightwards). [Note that Omega_B h^2 is held fixed here at the usual value of 0.0125. Varying h with Omega_B fixed would give a different result.]

Tilt+Tensors (50K)

We show the angular power spectrum change with decreasing amounts of tilt. All other parameters are held fixed at their sCDM values and n is increased from 0.7 to 1 (shown as the horizontal line at the top of the plot increasing rightwards). At the same time we add in tensors in the ratio T/S=7(1-n) [from power law inflation].

Time evolution of C_l (50k)

The angular power spectrum as it would be seen by observers living at different epochs. The scale factor increases logarithmically from a=1/2000 to a=1 (shown as the horizontal line at the top of the plot increasing rightwards). At early times, the higher moments are suppressed by tight coupling of the photons and baryons. The dominant effect after last scattering is the transfer of power from low to high ell, which is just caused by free streaming: the angle subtended by a given physical scale at last scattering becomes smaller as the distance to last scattering increases. One can also see the ISW effect operating.

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