Distance modulus: mod0

The distance modulus, mod0 [mag] is computed from the distance catalogue.

When measurements are available in the distance catalogue, mod0 is computed as the weighted average of those measurements.

Another parameter, modz (redshift distance modulus), estimates the luminosity-distance using the redshift. mod0 is essentially available for the closest galaxies for which the peculiar motions of the galaxy would make modz ineffective, while this latter, available for a wide redshift range, complement it when the recession velocity if greater than a few 1000 km/s. The two parameters, mod0 and modz are combined together to provide an homogeneous distance estimate over the whole redshit range: modbest.

HyperLeda Questions: leda@univ-lyon1.fr