QUASAR CONSTRAINTS ON THE COSMIC STRING MODELS

摘要

The number densities of quasars and high-redshift galaxies introduce strict constraints on theories of large-scale structure formation. We compute the comoving space densities of these objects with cosmic string models and compare results with observations. We show that the cosmic string models can produce enough high-density objects to account for the observations. We also show that, because of non-Gaussian initial conditions, the number density of quasars is higher than expected from conventional Gaussian Press-Schechter analysis. The cosmic string model is consistent with the QSO abundance limit at z = 4.5, both in Ω = 1.0 and in Ω = 0.2 cases. However, there are problems with large-scale structure when the "stringy" power spectrum is compared with the three-dimensional Automatic Plate Measuring Facility (APM) spectrum in Cambridge, England.