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12. Distance modulus and absolute magnitude

The kinematical distance modulus mucin can be derived from the heliocentric velocity properly corrected for the Local Group infall onto the Virgo cluster vvir assuming a given Hubble constant tex2html_wrap_inline2409. It must be noted that this distance does not include a correction for the infall of individual galaxies onto Virgo. Such a distance could have been calculated for instance using the model by Peebles (1976) as described in Bottinelli et al. (1986). However, this model does not allow the calculation in the direction of the Virgo center because of the third degree equation (Eq. (2) in Bottinelli et al. 1986). Further, this model requires the choice of a Virgo distance, of a Virgo mean radial velocity and of a velocity infall for the Local Group, while the calculation of mucin requires only the choice of the velocity infall for the Local Group (we adopted tex2html_wrap_inline2413 ; see Sect. 9). In the direction of Virgo cluster center mucin can be overestimated or underestimated depending on the background or foreground position of the considered galaxy with respect to Virgo center.

mucin is calculated only where tex2html_wrap_inline2419, mucin is available for 39243 galaxies. It is used to derive an estimate of the absolute magnitude amabs in Blue band:


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