IAU Symposium Abstract S186-009T

Tidal Disruptions of Galaxies in M81 Group

M. Yun1, P. Ho2, and K. Y. Lo3
1 National Radio Astronomy Observatory < myun@nrao.edu >
2 Smithsonian Astrophysical Observatory < pho@cfa.harvard.edu >
3 University of Illinois < kyl@sgr.astro.uiuc.edu >

The distribution and kinematics of neutral hydrogen (HI) surrounding M81 and its two companions (M82 & NGC 3077) are presented and discussed in terms of tidal interactions among the group members. At a distance of 3.3 Mpc, this group is situated far enough to map the distribution of stars and gas in the individual members easily at once while it is near enough to investigate with high spatial resolution (1''=15 pc) good sensitivity. The results of the numerical simulations of the group interactions are presented and discussed in context of mass distribution and tidal disruptions by the neighbors. New results from the 21cm HI absorption study against the background radio sources are also presented.