The Formation of Loose Groups

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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.***