Journal of Physical Studies 1(2), 287–296 (1997) DOI: https://doi.org/10.30970/jps.01.287 THE NUMBER DENSITY OF QUASARS AS A PROBE OF INITIAL POWER SPECTRUM ON SMALL SCALE

B. Novosyadlyj, Yu. Chornij
Astronomical Observatory of Lviv State University, 8 Kyrylo i Methodij Str., Lviv, UA-290005, Ukraine

The dependence of the number density of the bright QSOs at different redshifts ($n_{QSO}(z)$) on the initial power spectrum is studied. It is assumed that the QSO phenomenon is an early short term stage of evolution of massive galaxies with $M\geq 2\times 10^{11}h^{-1}M_{☉}$. The duration of such a QSO stage which is passed through by fraction $α$ of galaxies is determined by means of minimization of the divergence of the theoretical number density of QSOs at different redshifts for specified initial spectrum from the observable one \cite{sc91}. It is shown that the nearest number densities of QSOs at $0.7\le z\le 3.5$ to observable ones are obtained for the tilted CDM model ($Ω_{b}=0.1$, $n=0.7$). The QSO stage lasts $\sim 7\times 10^{7}/α$ years and begins soon after the moment of the rise of the first counterflow in collisionless component and of the shock wave in gas. The possibility of the reconstruction of the initial power spectrum on a small scale on the basis of the observable data on the number density of QSOs at different $z$ is considered too. Such reconstructed spectrum in comparison with the standard CDM has steep reducing of power at $k\ge 0.5 h Mpc^{-1}$.

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