Satellite Accretion and Disk Galaxies

 
Most galaxy interactions do not involve two large galaxies.

It is much more common for a small dwarf to interact with a larger host. What happens then?

 

Computer models of satellite mergers (Mihos & Hernquist 1995):
 

Top view
Side view

 
 
Satellite mergers can:
  • drive disk instabilities and bar formation

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  • drive inflow and starbursts

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  • lead to thickening and warping of the disk 

    •  
  • (more controversially) lead to bulge formation? 

    • Sc --> Sa?
(courtesy David Malin/AAO)

 
 
 
 
 
Satellite galaxies themselves are tidally stripped as they orbit their host...
 
 

(courtesy Kathryn Johnston)
...contributing to a stellar halo correlated in phase space (x,v)

(courtesy Paul Harding)