SIMBAD references

A Monte Carlo method for measuring the significance of possible space, velocity and/or luminosity segregation among galaxies of different Hubble types is presented. It relies on five statistical tests. This method is applied to a sample of early-type galaxies with reliable morphological classifications in the inner region of the Perseus cluster. A strong spatial segregation is detected: ellipticals are displaced eastward with respect to the cluster center, lenticulars northward, barred lenticulars southward, while disky ellipticals occupy the whole inner region of the cluster. This non-uniform distribution of morphological types is interpreted as an indication that the Perseus cluster, although claimed relaxed, is in reality not virialized and dynamically young. No statistically significant morphology-density or morphology-radius relations are detected showing that the primary source of the morphological segregation in this cluster is tied to the non-uniform spatial distribution of Hubble types and not to the local density or the distance from the cluster center. The number of spirals in the inner region of Perseus is underestimated in the literature by a factor 2 or 3. Finally, the bright ends of the luminosity functions of boxy and disky ellipticals do not differ statistically.