The origin of lopsidedness in galaxies
Abstract
It has long been known that a large fraction of disc galaxies are lopsided. We simulate three different mechanisms that can induce lopsidedness: flyby interactions, gas accretion from cosmological filaments and ram pressure from the intergalactic medium. Comparing the morphologies, HI spectrum and m=1 Fourier components, we find that all of these mechanisms can induce lopsidedness in the gaseous component of disc galaxies. In particular, we estimate that flybys can contribute to ~20 per cent of lopsided galaxies. We compare our simulations with the observations of NGC 891, a lopsided, edge-on galaxy with a nearby companion (UGC 1807). We find that the main properties of NGC 891 favour a flyby event for the origin of lopsidedness in this galaxy.
Cite
@article{arxiv.0808.4011,
title = {The origin of lopsidedness in galaxies},
author = {M. Mapelli and B. Moore and J. Bland-Hawthorn},
journal= {arXiv preprint arXiv:0808.4011},
year = {2008}
}
Comments
6 pages, 4 figures, to appear in "The Galaxy Disk in Cosmological Context"; Proceedings of IAU254; Copenhagen; 9-13 June 2008; eds. J. Anderson, J. Bland-Hawthorn, B. Nordstrom