CLUSTERS OF GALAXIES IN THE LONG COSMIC-STRING MODEL

We have tried to derive the characteristic features of clusters of gal axies from the cosmic-string model of galaxy formation in the flat uni verse dominated by cold dark matter. Clusters of galaxies are consider ed to be formed at around the crossing sites of three wakes of infinit ely long cosmic strings. From this point of view, we have examined the wake-crossing angle distribution among three wakes and have asked wha t kinds of velocity distribution are suitable for explaining various o bserved features, for example, the mass function of the clusters. We h ave calculated a number of cases of three wakes having crossing angles deviating from 90-degrees to derive the interpolated formula for the accumulated mass around the crossing point. To investigate the correla tion function of clusters of galaxies, we have distributed wakes of se veral sizes rather homogeneously with random orientations and then sea rched those crossing points whose crossing angles fall within a limite d range of values. The simulated results for the number density, the m ass function, and the correlation function of clusters of galaxies are in good agreement with observations under suitably adopted parameter values. We also estimate the mass functions of cold dark matter for gl obular clusters and galaxies in this model.