Analytical fit to the luminosity distance for flat cosmologies with a cosmological constant

摘要

We present a fitting formula for the luminosity and angular diameter distances in cosmological models with pressureless matter, a cosmological constant, and zero spatial curvature. The formula has a relative error of less than 0.4% for 0.2 < #OMEGA#_0 < 1 for any redshift and a global relative error of less than 4% for any choice of parameters.