流动有限和卷有限星系样品为统计分析从 Sloan 数字天空调查(SDSS ) 数据版本 DR4, DR6 和 DR7 被构造。二点的关联功能(s) ,三点的关联的单极工作 0,如果星系样品为这些统计是公正的,投射二点的关联功能 wp 和 pairwise 速度分散 12 被测量测试。我们发现与在 SDSS 的随后的数据版本的天空范围的增长,流动有限样品的(s) 对在低 redshift 的本地结构极其柔韧、感觉迟钝。然而,为卷有限取样比 L 微弱 * 逍遥法外规模 s 10 h ? 1 Mpc,从不同 SDSS 数据版本(DR7, DR6 和 DR4 ) 的(s) 的偏差与绝对大小的增长增加。0 (s) 的盒子类似于(s) 的。在弱非线性的政体,在在所有光明箱的 0 个不同数据版本之间没有协议。而且,卷有限的 wp 在比微弱的光明箱 DR7 取样 ? 先生, 0.1 =[18.5, 19.5 ] 显著地更大, DR7 的二件最微弱的卷有限样品中的 12 个从 DR4 和 DR6 比结果显示很不同的规模依赖。我们为在聚类分析的理解的小心的调查结果电话 SDSS 微弱星系样品和 SDSS 卷有限样品的更高的顺序统计导致弱非线性的政体。从卷有限样品的(s) 的第一个零十字路口的点也被调查并且讨论。
Flux-limited and volume-limited galaxy samples are constructed from the Sloan Digital Sky Survey(SDSS)data releases DR4,DR6 and DR7 for statistical analysis.The two-point correlation functionsξ(s),monopole of three-point correlation functionsζ0,projected two-point correlation function wp and pairwise velocity dispersionσ12 are measured to test if galaxy samples are fair for these statistics.We find that with the increment of sky coverage of subsequent data releases in SDSS, ξ(s)of the flux-limited sample is extremely robust and insensitive to local structures at low redshift.However,for volume-limited samples fainter than L* at large scales s~10 h-1 Mpc,the deviation of ξ(s)from different SDSS data releases(DR7,DR6 and DR4)increases with the increment of absolute magnitude.The case of ζ0(s)is similar to that ofξ(s).In the weakly nonlinear regime,there is no agreement between ζ0 of different data releases in all luminosity bins.Furthermore,wp of volume-limited samples of DR7 in luminosity bins fainter than -Mr,0.1=[18.5,19.5]are significantly larger and σ12 of the two faintest volume-limited samples of DR7 display a very different scale dependence than results from DR4 and DR6.Our findings call for caution in understanding clustering analysis results of SDSS faint galaxy samples and higher order statistics of SDSS volume-limited samples in the weakly nonlinear regime.The first zero-crossing points of ξ(s)from volume-limited samples are also investigated and discussed.