QUASARS AND LARGE SCALE STRUCTURE OF THE UNIVERSE

The majority of bright distant quasars $(z {}^{>}_{\sim} 1)$ may form in massive mergers appearing in compact galaxy groups in/and young clusters. The expected tests are (i) large correlation signal for medium-$z$ QSOs $(1 < z < 2)$ and (ii) direct search for quasar groups (QGs) indicating positions of distant pre-superclusters which later will evolve to the "systems" like the local Great Attractor or Shapley concentration. We discuss large QGs with more than ten members within regions $\le l_{LS} \sim 100-150 \, h^{-1} Mpc$, tracing the enhanced density regions at $z {}^{<}_{\sim} 2$. These early large scale structures (i) provide a natural way to "bias" the distribution of Abell clusters, and (ii) suggest that the spectrum of primordial density perturbations is nearly flat at scales encompassing both cluster and GAs, $l = \pi k^{-1} \in(10,100)h^{-1} Mpc: \Delta^{2}_{k} \sim k^{3}P(k) \sim k^{\gamma}, \gamma = 1^{+0.6}_{-0.4}$.