A dynamical-mass survey of nearby clusters of galaxies

本研究的目的是制作一台多狭缝摄谱仪，并测量邻近星系团中星系的后退速度，以推导出这些星系团的引力质量。我们于1997年制作了摄谱仪，并对其性能进行了验证。我们还开发了软件来测量光谱数据的红移。最初，我们计划在1997年进行观测。然而，由于我们无法获得适当的1米级望远镜的观测时间，我们没有进行观测。相反，根据我们现有的数据，我们做了以下研究。我们开发了一个程序来自动从星系的成像数据中找到星系团。我们还使用真实的数据验证了它的性能.我们研究了后发座星系团中矮星系的性质，发现后发座矮星系的光度性质与前座星系团中的矮星系相似，都是（与后发座星系团相比）不规则的、较差的光泽。这一事实表明，矮星系的性质可能是普遍的，与环境无关。我们推导出星系光度函数（LF）的基础上，我们的宽视场光度数据附近的10个集群。我们发现，虽然星系团之间的低频形状不同，但十个星系团的平均形状与场星系的低频形状是一致的。我们还发现，类型相关的LF的形状是普遍的集群之间。

The purpose of this study was to make a multislit spectrograph and to measure recession velocities of galaxies in nearby clusters to derive the gravitational masses of those clusters. We made the spectrograph in 1997 and verified its performance. We also developed software to measure redshifts from spectral data. Orginally, we planned to carry out observations in 1997. However, since we could not obtain observing times of appropriate, 1-m class telescopes, we did no observations. Instead, on the basis of our available data, we did the follwing studies.1. We developed a program to automatically find clusters from imaging data of galaxies. We also verified its performance using real data.2. We studied the properties of dwarf galaxies in the Coma Cluster, and found that the photometric properties of Coma dwarfs resemble those of dwarf galaxies in the Vorgo Cluster, which is (in contrast with Coma) an irregular and poor luster. This fact suggests that the properties of dwarf galaxies may be universal irrespective of environments.3. We derived the galaxy luminosity functions (LF) for nearby 10 clusters on the basis of our wide-field photometric data. We found that though the shapes of LFs vary among clusters, the shape averaged over the ten clusters is consistant with the shape of LF of field galaxies. We also found that the shapes of type-dependent LFs are universal among clusters.