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Journal of Physical Studies 14(2), Article 2901 [5 pages] (2010)
DOI: https://doi.org/10.30970/jps.14.2901 SPACE NUMBER DENSITY OF BRIGHT QUASARS IN THE HALO MODEL OF GALAXY FORMATIONYu. Kulinich, B. Novosyadlyj
Astronomical Observatory of Ivan Franko National University
of Lviv, |
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We analyse the redshift dependence of space number density of quasars assuming that they are the short-lived active stages of the massive galaxies and arise immediately after the collapse of the homogeneous central part of protogalaxy clouds. The obtained dependence fits very well observational data of ChaMP$+$CDF$+$ROSAT [J. D. Silverman {\em et al.}, Astrophys. J. {\bf 624}, 630 (2005)] for protogalaxy clouds of the mass of $M≈ 8\cdot 10^{11}$ $h^{-1}M_{☉}$ and the ellipticity of $e<0.4$. The lifetime of the bright X-ray AGNs or QSOs with $L_X>10^{44.5}$ erg$\cdot {\rm s}^{-1}$ in the range of energies $0.3-8$ keV is $τ_{\rm QSO}\sim 6\cdot10^6$ years when the mass of supermassive black hole is $M_{\rm SMBH}\sim 10^{9}$ $M_{☉}$ and the values of other quasar parameters are reasonable. The analysis and all calculations were carried out in the framework of the $Λ$CDM-model with the parameters determined from 5-years WMAP, SNIa and large scale structure data [E. Komatsu {\em et al.}, Astrophys. J. Suppl. Ser. {\bf 180}, 330 (2009)]. It is concluded that the halo model of galaxy formation in the $Λ$CDM cosmological model matches well observational data on AGNs and QSOs number density coming from current optical and X-ray surveys.
PACS number(s): 98.54.Aj, 98.54.Kt, 98.54.-h, 98.65.Fz, 98.35.Jk