Annu. Rev. Astron. Astrophys. 1994. 32: 319-70 Copyright © 1994 by Annual Reviews. All rights reserved

APPENDIXES

A. Some Useful Numbers

Converting from multipole space to angles is accomplished via the approximate formula

(37)

It is this equality that is used to make statements that certain measurements are on a scale of . This correspondence, ^-1 radians, seems most natural for large [cf the window function, Equation (28)]; for small , it may be better to think of / radians, but in any case the correspondence is not exact. At any z >> 1, an angle degrees subtends a comoving distance of 105 (₀ h)^-1 Mpc.

To convert from to comoving wavenumber k we have ~ (6, 000h^-1 Mpc)k. Additionally we have the physical scales (at horizon crossing)

(38)

The redshifts of equality, recombination, and decoupling (Compton cooling) for standard recombination are

(39)

and for reionization with constant ionized fraction x_e

(40)

The following angles are also useful:

(41)