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We model the formation of Aurigas Wheel - a recently discovered collisional ring galaxy. Aurigas Wheel has a number of interesting features including a bridge of stars linking the neighbouring elliptical to the ring galaxy, and evidence for components of expansion and rotation within the ring. Using N-body/SPH modelling, we study collisions between an elliptical galaxy and a late-type disk galaxy. A near direct collision, with a mildy inclined disk, is found to reasonably reproduce the general system morphology ~50 Myr following the collision. The collision must have a relatively low velocity (initially ~150 km s^{-1}) in order to form the observed bridge, and simultaneously match the galaxies separation. Our best-match model suggests the total disk galaxy is ~5 times more massive than the elliptical. We find that the velocity of expansion of the ring is sensitive to the mass of the elliptical, while insensitive to the encounter velocity. We evolve our simulation beyond the current epoch to study the future destiny of the galaxy pair. In our model, the nucleus moves further away from the plane of the ring in the direction of the stellar bridge. The nucleus eventually merges with the elliptical galaxy ~100 Myr after the present time. The ring continues to expand for ~200 Myr before collapsing back. The low initial relative velocity of the two galaxies will eventually result in a complete merger.
We have found the peculiar galaxy NGC922 to be a new drop-through ring galaxy using multi-wavelength (UV-radio) imaging and spectroscopic observations. Its `C-shaped morphology and tidal plume indicate a recent strong interaction with its companion w
The diversity of structures in the Universe (from the smallest galaxies to the largest superclusters) has formed under the pull of gravity from the tiny primordial perturbations that we see imprinted in the cosmic microwave background. A quantitative
The Galaxy Ultraviolet Explorer (GALEX) satellite has recently shown the presence of an extended, outer ring studded with UV-bright knots surrounding the lenticular galaxy NGC 4262. Such a structure---not detected in the optical---is coupled with a r
We revisit the case of fast Monte-Carlo simulations of galaxy positions for a non-gaussian field. More precisely we address the question of generating a 3D field with a given one-point function (as a log-normal one, but not only) and some power-spect
A new method is presented for modelling the physical properties of galaxy clusters. Our technique moves away from the traditional approach of assuming specific parameterised functional forms for the variation of physical quantities within the cluster