The Formation of Loose Groups

MPS-0104439 PI：丹尼尔J. PisanoDr.皮萨诺将在澳大利亚国家望远镜设施开展一项研究计划，作为MPS杰出研究博士后研究员。 他的研究将集中在松散星系群的HI特性上，以解决我们银河系和其他更遥远星系形成的有争议的模型。 大多数星系，包括我们自己的星系，都居住在群体中，尽管对松散群体的许多性质，如我们自己的本星系群，了解得相对较少。 例如，我们不知道松散的星系群是否仍在聚集，或者环境如何影响这些星系群的成员。 一些星系形成模型认为，数以百计的暗物质晕应该存在于松散的群体中。 也许银河系周围的高速云与这些暗物质晕有关，是与本星系群形成有关的气体碎片。 如果这些理论是正确的，那么高速云和卫星星系的类似物也应该存在于其他松散的星系群中。 这项研究计划将通过对松散星系群的HI和光学观测来检验这些假设，这将寻找松散星系群中高速云的存在，并探测低质量、富含气体的星系。这项研究由数学和物理科学局多学科活动办公室资助。

MPS-0104439PI: Daniel J. PisanoDr. Pisano will carry out a program of research as an MPS Distinguished Research Postdoctoral Fellow at the Australian National Telescope Facility. His research will focus on the HI properties of loose groups of galaxies, in an effort to resolve controversial models for the formation of our Milky Way Galaxy and others more distant galaxies. Most galaxies, including our own, reside in groups, although many properties of loose groups, such as our own Local Group, are relatively poorly understood. It is not known whether loose groups of galaxies are still assembling, for example, or how the environment affects members of these groups. Some galaxy formation models suggest that hundreds of dark matter halos should exist in loose groups. Perhaps the high velocity clouds seen around the Milky Way are associated with these dark matter halos and are the gaseous debris associated with the formation of the Local Group. If these theories are correct, then the analogs of high velocity clouds and satellite galaxies should exist in other loose groups as well. This research program will test these hypotheses, with HI and optical observations of loose groups of galaxies, that will search for the presence of high velocity clouds in loose groups and detect low-mass, gas-rich galaxies. This research is funded through the Office of Multidisciplinary Activities in the Directorate for Mathematical and Physical Sciences.***