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

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,
000*h*^{-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) |