我们分析了来自O 'Mill et al.(2012)工作的71个发光星系的三胞胎样本。我们比较的性质的三胞胎和他们的成员与控制样本的紧凑的群体,10个最明亮的成员丰富的集群,和星系对。三重态被限制为具有光谱红移在0.01<z<0.14和Mr<-20.5范围内的成员。我们分析了恒星质量(SM)含量,恒星形成率,Dn(4000)参数和颜色指数,并分析了这些系统的不同的整体性质,总恒星形成活动和整体颜色。我们计算了三重星系的性质是强相关的概率。我们将三重态紧密度定义为成员星系的光占系统总面积的百分比。我们的分析表明,三重星系成员的行为类似于紧凑的集团成员和星系丰富的集群。我们还发现,由3个蓝色的、形成恒星的、年轻的恒星星族星系(蓝色三胞胎)组成的系统很可能是真实的系统,而不是偶然的星系配置。这同样适用于由3个红色,非恒星形成星系组成的三胞胎,显示了这些系统中星系属性的相关性。从作为一个整体的三胞胎的分析,我们得出结论,在一个给定的总SM含量,三胞胎显示出总的恒星形成活动和全球的颜色类似于紧凑的群体。然而,蓝色三胞胎显示出高的总恒星形成活动与较低的SM含量。从系统的紧凑性参数的分析,我们发现,光更集中在三重态比在紧凑的群体。我们认为由3个发光星系组成的三胞胎不应该被认为是具有额外成员的星系对的类似物,而是紧凑群体的自然延伸。
英文摘要:
We analyse a sample of 71 triplets of luminous galaxies derived from the work of O'Mill et al. (2012). We compare the properties of triplets and their members with those of control samples of compact groups, the ten brightest members of rich clusters, and galaxies in pairs. The triplets are restricted to have members with spectroscopic redshifts in the range 0.01<z<0.14 and Mr<-20.5. We analyse the stellar mass (SM) content, the star formation rates, the Dn(4000) parameter and colour index and also analyse different global properties of these systems as total star formation activity and global colours. We calculate the probability that the properties of galaxies in triplets are strongly correlated. We define the triplet compactness as a measure of the percentage of the system total area that is filled by the light of member galaxies. Our analysis suggest that triplet galaxy members behave similarly to compact group members and galaxies in rich clusters. We also find that systems comprising 3 blue, star-forming, young stellar population galaxies (blue triplets) are most probably real systems and not a chance configuration of interloping galaxies. The same holds for triplets composed by 3 red, non star-forming galaxies, showing the correlation of galaxy properties in these systems. From the analysis of the triplet as a whole, we conclude that, at a given total SM content, triplets show a total star formation activity and global colours similar to compact groups. However, blue triplets show a high total star formation activity with a lower SM content. From an analysis of the compactness parameter of the systems we find that light is even more concentrated in triplets than in compact groups. We propose that triplets composed by 3 luminous galaxies, should not be considered as an analogous of galaxy pairs with an extra member, but rather they are a natural extension of compact groups.
The Size, Shape and Orientation of Cosmological Voids in the Sloan Digital Sky Survey
我们提出了一个详细的描述,我们的空洞发现算法,这是一个由Hoyle和Vogeley(2002)的处方的扩展。我们包括一个讨论的算法的再现性和鲁棒性,以及检测到的空隙的统计意义。我们将我们的空洞发现者应用于斯隆数字巡天(SDSS)的数据发布5(DR5),并确定了232个宇宙学空洞。将创建包含检测到的空隙的最显著属性的空隙目录。我们提出了一个我们确定的宇宙学空洞的大小,形状和方向的分布的统计分析。我们还研究了红移为0.04 < z < 0.16的可能趋势。我们比较我们的结果,从一个相同的分析模拟目录的基础上的LambdaCDM模型,并找到合理的协议。然而,宇宙学空洞的总体方向存在一些统计学上的显著差异,需要通过进一步改进模拟来加以调和。
Four New Observational $H(z)$ Data From Luminous Red Galaxies of Sloan Digital Sky Survey Data Release Seven
采用微分年龄法,利用Sloan数字巡天数据7(SDSS DR 7)中包含红移$0<z<0.4$的17832个亮红星系(LRGs)测量哈勃参数。利用全谱拟合软件UlySS,用单星族(SSP)模型对这些光谱进行了约简,并得到了我们所选样本的最佳年龄信息。随着年龄-红移关系的减小,获得了4个新的观测$H(z)$数据点,它们分别是$H(z)=69.0\pm19.6$ km s $^{-1}$ Mpc $^{-1}$ at $z=0.07$,$H(z)=68.6\pm26.2$ km s $^{-1}$ Mpc $^{-1}$ at $z=0.12$,$H(z)$ = $72.9\pm29.6$ km s $^{-1}$ Mpc $^{-1}$ at $z=0.2$和$H(z)$ = $88.8\pm36.6$ km s $^{-1}$ Mpc $^{-1}$ at $z=0.28$.结合其他21个OHD数据点,给出了平面和非平面$Λ$ CDM模型的约束性能。
The Pittsburgh Sloan Digital Sky Survey MgII Quasar Absorption-Line Survey Catalog
我们提出了一个红移区间为0.36 <= z <= 2.28的镁II类星体吸收线系统的目录。该星表由斯隆数字巡天数据发布4(SDSS DR 4)类星体光谱构建。目前,该目录包含> 17,000个测量的MgII双峰。我们还提供了用于构建目录的~ 44,600个类星体光谱的数据,包括红移和星等信息,连续归一化光谱,以及在我们的置信阈值下可检测到的红移相关最小静止等效宽度的相应阵列。该目录可在网上查阅。仔细的第二次搜索的500个随机光谱表明,每100个光谱搜索,大约一个显着的MgII系统被意外拒绝。目前的计划,扩大目录以外的DR 4类星体进行了讨论。已知许多MgII吸收体与星系有关。因此,结合大尺寸和充分理解的统计数据,使这个目录的理想精密研究的低电离和中性气体区域与星系在低到中等红移。使用该目录的MgII吸收剂的统计分析将在随后的论文中提出。
Direct Minkowski Functional analysis of large redshift surveys: a new high--speed code tested on the luminous red galaxy Sloan Digital Sky Survey-DR7 catalogue
Observational Upper Bound on the Cosmic Abundances of Negative-mass Compact Objects and Ellis Wormholes from the Sloan Digital Sky Survey Quasar Lens Search