The distance modulus, `modbest [mag]` is a weighted average between `mod0` and `modz` (the weight are the inverse square of the estimated errors on each parameter).

The distance modulus is related to the luminosity distance, expressed in Mpd, through the relation: `modbest = 5 log(D _{L}) + 25 `

Note that in cosmology other distances can also be defined, the proper distance (based on the Hubble expansion), and the angular-diameter and comoving distances. A modulus based on a luminosity-distance, like

`modbest` is used to derive the absolute magnitude `mabs`.

HyperLeda | Questions: leda@univ-lyon1.fr |