类星体的光度演化函数Ⅰ：包括Z＞2．2大红移范围的统计演化函数

THE OPTICAL EVOLUTION FUNCTION OF QSOs Ⅰ:STATISTICAL EVOLUTION FUNCTION OF QSO_s(REDSHIFT EXTENDED TO Z>2.2)V

本文对前人的类星体光学演化函数进行改进，使其适用于更大的红移范围，可达Ｚ＝３以上。其物理考虑是：一方面包括核心黑洞质量和吸积率变化而引起光度演化；另一方面在高红移时类星体诞生所引起的密度演化，并且这种演化率与光度有关。这种型式更利于与类星体演化的动力学模型相衔接。新的演化函数通过三种检验来决定，即（１）类星体直到ｍ＝２２ｍ．０的星等计数，（２）以ΔＺ＝０．１为间隔的红移分布，（３）Ｚ＞２的类星体的星等计数。在适当的光学演化参数和诞生参数下，我们的演化函数与上述三项观测对比相当好，理论预言在观测误差之内。特别要强调的是改善了其它演化函数理论预言在Ｚ＞２普遍过剩的行为，因此这个演化函数可作为类星体演化动力学模型的依据之一。

n this paper, we present a modified optical evolution function of QSOs which is adequate for high redshift, even for z=3.3. The physics consideration is based on luminosity evolution resulted from both the variances of the mass and the accretion rate of central object and luminosity-dependent density evolution due to the birth of QSOs at high redshift. This evolution function is more convenient for describing the dynamical characters of QSO evolution, and it can be determined through comparison with the following three observed results: (1) Magnitude counts of QSOs up to m=22m.0. (2) Redshift-distribution of QSOs over interval ΔZ=0.1.(3) Magnitude counts of QSOs with Z>2. If the parameters of the luminosity evolution and of the birth of QSOs are adopted properly, the new evolution function can be consistent with the above three observed results, and the predicted results are within the observational errors. Worthy of special mention is that it improves the excess feature at Z>2 predicted by other evolution functions. Therefore this new evolution function can be considered as a basis for dynamic models of QSO evolution.