【摘要】 利用已知的统计结果对高红移类星体光谱进行ＭｏｎｔｅＣａｒｌｏ模拟，得到了ＵＢＶＲＩ五色测光的色指数，并利用模拟的选择判据计算了选择效应函数，当２．４＜ｚ＜３．０时，选择效应来自于与主序星的混淆；当ｚ＞３．０时，则是由于较暗的类星体与晚型矮星同时从Ｕ．Ｂ等颜色的图象上消失，导致可利用色指数的减少。更多还原

【Abstract】 Using well established statistical properties of QSO absorptions,the computer Monte─Carlo simulation spectra for QSOs with different redshift are constructed and are used to calculate the color indices in U,B,V,R, I system. Selection function is defined and is computed based on the simulated spectra. The main results are: (1)for 2.4<z<3.0, selection effects come from the confusion of QSO with main sequence stars, and (2) for z>3.0,faint QSOs and late─type dwarfs are outside the detection limit in U,B and even V bands,causing less color indices be used for selecting QSOs. The limitations of wide─band photometry currently used for high redshift QSO survey are discussed, and the narrow bands survey is suggested.更多还原