QUASAR CONSTRAINTS ON THE COSMIC-STRING MODELS

The number densities of quasars and high-redshift galaxies introduce s trict constraints on theories of large-scale structure formation. We c ompute the comoving space densities of these objects with cosmic strin g models and compare results with observations. We show that the cosmi c 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 mod el is consistent with the QSO abundance limit at z = 4.5, both in Ohm = 1.0 and in Ohm = 0.2 cases. However, there are problems with large-s cale structure when the ''stringy'' power spectrum is compared with th e three-dimensional Automatic Plate Measuring Facility (APM) spectrum in Cambridge, England.