The Luminosity Function of Quasars

An entire review of the history and present status of research on the luminosity function of quasars is given in this paper. Based on previous works, two new methods and a new statistical test are proposed. The first is the classification method. In this method, quasars are divided into several subclasses. The luminosity evolution form of each subclass can be determined by correlation analysis and the density law of the subclass can be obtained by simple number-counting. The second is the mean magnitude method. A mean absolute magnitude is defined. The study shows that, in the pure density evolution model, independents redshiftz, while in the pure luminosity evolution model, is linearly correlated with the luminosity evolution form (Ｍ_z－Ｍ^*). The new statistical test is the n/n max test. It is a generalization of the V/V_maxandV'/V'_maxtests. Unlike the conventional ones, it could be applied to any luminosity function models. If the adopted luminosity function is correct, the values of the statistic n/n max would be uniformly distributed in the interval.