The horizon size at the last

The horizon size at the last - The horizon size at the...

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The horizon size at the last-scattering surface, important not only for big questions of causal connectivity but in the growth of perturbations, is 184 (Ω h²) -1/2 Mpc. The spectrum of fluctuations (usually considered as a power spectrum in wavenember l of, for example, Bessel functions on the sphere) is highly diagnostic of processes in the early Universe, which has driven much of the work on improving maps of structure in the CMBR. We expect a Sachs-Wolfe "plateau" for small values of l , leading to an acoustic (or Doppler) peak. The location of this peak is sensitive to both Ω and Λ, while its amplitude is sensitive almost purely to Ω. Models also predict that harmonics of this peak should be seen to higher values of l . These may be explored with the publicly released CMBFAST code (see Seljak and Zaldarriaga 1996 ApJ 469, 437, more recently updated to include both closed and open geometries, with the interesting difference that only spatially wrapped spherical wavenumbers are allowed in the closed case). This typical prediction was taken from the
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The horizon size at the last - The horizon size at the...

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