mabs , the B-band absolute magnitude is computed from the corrected magnitude btc and the distance modulus modz (from the redshift) or mod0 (redshift-independent). For nearby galaxies ( v < 500 km/s, modz is not computed because it would be too imprecise (the peculiar motions dominate the Hubble flow), and the absolute magnitude is computed as: mabs = btc - mod0 For more distant galaxies, it is computed as: mabs = btc - modz . HyperLeda . Questions: leda@univ-lyon1.fr