It is defined as

D_{L} is derived from the cosmological redshift, assuming the
following values for the
Hubble constant and other cosmological parameters:

The choice of `vvir` to estimate
the cosmological redshift is a compromise.
For large distances, `v3k` should be
more appropriate. But the galaxies of the Local Universe share a similar
bulk motion as the Galaxy, and correcting only the motion of the Galaxy
would bias their distance determination.
An improvement would be to use a model for the bulk motions in the
Local Universe.

The parameter `mod0` (redshift-independent modulus) is an estimate of the
luminosity-distance independently of the redshift, and both parameters are combined into `modbest`, to provide the best distance estimate at any redshift.

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