Cosmic Strings and Structure Formation

Abstract

We discuss structure formation in cosmic string theories. Emphasis is laid on the properties of the peculiar velocity field, non-gaussian features and clusters of galaxies. It is found that the predicted peculiar velocity field is quiet ($v<150$ km/s for $L>30h^{-1}$ Mpc) for models with ($\hat{I}{\text{c◯}}_{0}h\le 0.2$) which is in disagreement with the results from POTENT at large scales ($>30h^{-1}$ Mpc), consistent, however, with the analysis of the peculiar velocity field of spiral galaxies by Giovannelli et al.. Using the Press-Schechter formalism we calculate the abundances of X-ray clusters. It is found that in CDM models a mass fluctuation $\ddot{I}{ƒ}_8=\mathrm{0.6...0.7}$ is needed with $\hat{I}{\text{c◯}}_{0}h=\mathrm{0.1...0.2}$ in order to explain the current data.

15 pages, latex, 8 embedded figures. To appear in the proceedings of the Second International Workshop on Dark Matter (DARK98), eds. H.V. Klapdor-Kleingrothaus and L. Baudis