Distance Calculator

Cosmological Distance Calculator

Computes distances and times from a flat (or curved) FRW model. Defaults to Planck 2018 ΛCDM. $\Omega_k$ is inferred as $1 - \Omega_m - \Omega_\Lambda - \Omega_r$.

The numerical integration uses composite Simpson’s rule on $\int_0^z dz'/E(z')$ with $E(z) = \sqrt{\Omega_r(1+z)^4 + \Omega_m(1+z)^3 + \Omega_k(1+z)^2 + \Omega_\Lambda}$. Curvature handling follows Hogg, Distance measures in cosmology (astro-ph/9905116).