IAU Symposium Abstract S186-034P

An interaction model of M81, M82 and NGC3077

R. C. Thomson1 and S. Laine2
1 University of Hertfordshire, Hatfield, UK < rct@star.herts.ac.uk >
2 University of Hertfordshire, Hatfiled, UK < seppo@star.herts.ac.uk >

An interaction model of the M81, M82, and NGC~3077 system will be presented. Using a full N-body/SPH treatment, we follow the evolution of a strong prograde interaction between M81 and another less massive spiral progenitor including active dark matter haloes. We are particularly interested in seeing whether M82 can be formed as a dusty, gas-rich shred of material torn from the disc of the spiral progenitor during the strong prograde interaction with M81 some 100 Myr ago. We expect the robust bulge of the spiral progenitor to survive the collision to form the peculiar dwarf elliptical galaxy NGC~3077. If successful, this model could explain the apparent coincidence implied by other interaction models that both M82 and NGC~3077 interacted with M81 at about the same time. The resulting gas distribution and velocity field will be compared with the published HI maps of this system.