【摘要】 基于NASA/IPAC河外星系数据库（NASA/IPAC Extragalactic Database,NED）和Sloan数字巡天（Sloan Digital Sky Survey,SDSS）第8次释放的数据（The Eighth Data Release,DR8）,对星系团Abell 85（以下简称A85）的2倍动力学特征半径2r₂₀₀内的光度函数（Luminosity Function,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M_r^*=-21.14_-0.17^+0.17mag,α=-0.83_-0.14^+0.12,晚型星系为M_r^*=-21.98_-0.98^+0.84mag,α=-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^-20.0 mag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.更多还原

【Abstract】 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 dynamical 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 at the faint end of the luminosity function） of Schechter function are M_r^*=-21.14_-0.17^+0.17mag and α=-0.83_-0.14^+0.12 for early-type galaxies,and M_r^*=-21.98_-0.98^+0.84 mag and α=-1.5_-0.35^+0.24for late-type galaxies,respectively.The LF of early-type galaxies shows a dip around M_r^*≈-20.5 to-20.0 mag.We also investigate the LFs in three cluster-centric annuli within1.5r₂₀₀,and find that the closer the distance from the cluster center,the steeper the faintend slope,and the brighter the characteristic magnitude.更多还原