Collaborative Research: Probing Galaxy and Cluster Halos Using Dwarf Galaxies

马特奥和奥尔谢夫斯基博士将使用马特奥博士建造的麦哲伦望远镜上的光谱仪，测量矮小星系内恒星的运动。这些亮度最低的星系似乎比恒星的质量大得多：我们观察到这些恒星的运动速度如此之快，如果没有看不见的暗物质的额外引力，它们就会逃离银河系。通过对恒星运动的仔细研究，该小组将改进对附近矮小星系总质量的测量，并测试它们是否被邻近星系的引力拉开。在更远的星系中，他们将测量周围球状星团的运动，以估计星系的质量，从而估计其暗物质的质量。该小组将与统计学家合作，分析和解释他们的结果。这项工作的结果将检验星系形成的理论，其中许多理论预测星系必须超过最小质量才能继续形成恒星。学生将在参与研究的同时接受培训。Mateo博士和Olszewski博士都将就他们在当地社区的工作发表公开演讲。通过亚利桑那大学的一个项目，奥尔谢夫斯基博士将继续与小学教师合作，举办明星派对，并参观斯图尔德天文台的望远镜。

Drs Mateo and Olszewski will measure the motions of stars within dwarf galaxies, using a spectrograph at the Magellan telescope built by Dr. Mateo. These least-luminous of the galaxies appear to contain far more mass than is present as stars: we observe those stars to be moving so rapidly that they would escape from the galaxy if not for the additional gravitational pull of unseen dark matter. By careful studies of stellar motion, the group will improve measurements of the total mass present in nearby dwarf galaxies, and test whether they are being pulled apart by gravitational forces from neighbor galaxies. In more distant galaxies, they will measure motions of the surrounding globular star clusters to estimate the mass of the galaxy and hence of its dark matter. The group will collaborate with statisticians to analyze and interpret their results. The results of this work will test theories of galaxy formation, many of which predict that a galaxy must exceed a minimum mass in order to continue making stars. Students will be trained as they participate in the research. Both Dr Mateo and Dr. Olszewski will present public lectures on their work in their local communities. Through a program at U. Arizona, Dr. Olszewski will continue his work with elementary-school teachers, with star parties and visits to the Steward Observatory telescopes.