中文摘要：

基于NASA／IPAC河外星系数据库（NASA／IPACExtragalacticDatabase，NED）和Sloan数字巡天（SloanDigitalSkySurvey，SDSS）第8次释放的数据（TheEighthDataRelease，DR8），对星系团Abell85（以下简称A85）的2倍动力学特征半径2r200内的光度函数（LuminosityFunction，LF）进行了研究．研究表明，A85的光度函数在Sloan巡天5个波段用Schechter函数均能拟合得很好．在U、g和Z波段光度函数都显示出1个下凹．早型星系r波段的两个最佳拟合参数（r波段特征绝对星等和暗端的陡度）分别为Mr＊=-21.14-0.17^＋0.171；mag，Q=-0．83±-0.14^＋0.12晚型星系为Mr＊=-21.98-0.98^＋0.84mag，a=-1．5-0.35^＋0.24.早型星系的特征星等暗于晚型星系，而暗端比晚型星系要平坦得多．早型星系的光度函数在-20．5--20．0mag下凹．将1．5r200范围内的星系按距离团中心的远近划分为3个环状区域，发现距离团中心越近，光度函数的暗端越陡，特征星等越亮．

英文摘要：

We present the luminosity function （LF） of the galaxy cluster Abell 85 based on the photometric and spectroscopic data from NASA/IPAC Extragalactic Database （NED） and the Eighth Data Release of Sloan Digital Sky Survey （SDSS-DR8） within the dynami- cal radius 2r200. It is shown that the LF of A85 can be fitted well with a single Schechter function in all five bands from SDSS, and a dip is shown in u, g, and z bands, respectively. The best-fitting parameters （the characteristic absolute magnitude in r band and the slope ＂）1 1A＋0.17 mag at the faint end of the luminosity function） of Schechter function are Mr＊=-21.14-0.17^＋0.171;mag,Q=-0.83±-0.14^＋0.12 for early-type galaxies, andMr＊=-21.98-0.98^＋0.84mag,a=-1.5-0.35^＋0.24 for late-type galaxies, respectively. The LF of early-type galaxies shows a dip around M＊ -20.5 to -20.0 mag. We also investigate the LFs in three cluster-centric annuli within 1.5r2oo, and find that the closer the distance from the cluster center, the steeper the faint- end slope, and the brighter the characteristic magnitude.