Year: 1986
Type: article
Abstract: Gravitational drag on satellite galaxies of a disc galaxy has been studied. A variety of computer models were used to simulate the galaxy: a ‘cold’ Mestel disc with no velocity dispersion, and a more realistic ‘hot’ disc with a velocity dispersion inside an inert spherical halo were studied. Simulations were performed with a two-dimensional polar coordinate N-body program by Miller. About 60000 particles were used in the disc and satellites of 0.05 and 0.1 disc mass were studied. Satellite orbits were initially of zero energy with various encounter distances from the disc. We find for hot and cold discs with or without haloes that the energy change due to tidal interaction is always negative, i.e. the satellite becomes more strongly bound. The strongest effect is for a cold disc and a direct satellite orbit. Our cold disc results are opposite to those analytically calculated by Palmer & Papaloizou; however, their recent analytic results for a hot disc agree with ours for a hot disc in an inert spherical halo. Much greater energy absorption for direct rather than retrograde satellite orbits implies a dependence on inclination qualitatively matching Holmberg's observation of few satellites near the disc plane of edge-on spirals. For our results to explain those of Holmberg disc masses must be comparable to halo masses in spiral galaxies.
Authors: G. G. Byrd, S. Saarinen, M. J. Valtonen
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2141697002