black holes, $\tau_{AGN}\sim 8\cdot 10^6$ yr ($ 2\cdot 10^{6}-5\cdot 10^{7}$ yr) for their life-time and $\eta \sim 0.14$ for their efficiency (always for a $\Lambda CDM$ model).
author:
- Andrea Grazian
- Mattia Negrello
- Lauro Moscardini
- Stefano Cristiani
- 'Martin G. Haehnelt'
- Sabino Matarrese
- Alessandro Omizzolo
- Eros Vanzella
title: |
    The Asiago-ESO/RASS QSO Survey\
    III. Clustering analysis and its theoretical interpretation[^1]
---

Introduction
============

The analysis of the statistical properties (luminosity function and clustering) of the cosmic structures is a fundamental cosmological tool to understand their formation and evolution. The clustering of QSOs and galaxies at small to intermediate scales (1-50 $h^{-1}$ Mpc) provides detailed information on the distribution of Dark Matter Halos (DMHs) that are generally thought to constitute the “tissue” on which cosmic structures form. This means to investigate –indirectly– fundamental astrophysical problems, such as the nature of dark matter, the growth of structures via gravitational instability, the primordial spectrum of density fluctuations and its transfer function. The lighting up of galaxies and other luminous objects, such as QSOs, involves complex and non-linear physics. It depends on how the baryons cool within the DMHs and form stars or start accreting onto the central 