... Group

We note that the observer at the centroid would measure a slightly different velocity, depending on the location of the galaxy and the nature of the velocity field close to the Local Group. For example, if the deviation of the velocity field from the Hubble flow is exactly spherically symmetric relative to the centroid, one may show by starting from the first principles of the Hubble velocity field that then the observer at the centroid would see the velocity $V_{\rm Yahil}/\cos\theta$. $\theta$is the angle between the centroid and the Galaxy as seen from the measured galaxy. In the present case, $\theta$ is normally quite small. Hence such a correction makes the velocity usually only 1-5 kms^-1 larger for our field galaxies. We prefer here to use the simpler velocity correction as done by Sandage (1986).

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