A Merger Origin for X-Structures in S0 Galaxies
Abstract
Using numerical simulation, we study the response of a disk galaxy to a merger involving a low-mass satellite companion. During a prograde satellite accretion, the disk galaxy forms a strong bar in response to the perturbation of the companion. After the accretion event is over, the bar buckles vertically due to a bending instability, sending disk material well out of the disk plane. The material forms into an X-shaped feature when seen edge-on, morphologically similar to X-structures observed in several S0/Sa galaxies. The mechanism described here unites previously suggested accretion and bar instability hypotheses for forming X-structures into a self-consistent scenario for merger-induced formation and evolution of S0 galaxies. To complement these models, we also present observations of the peculiar S0 galaxy Hickson 87a. The thick disk, isophotal warping, and strong X-structure described in the merger model are all evident in Hickson 87a, suggesting this galaxy may be an excellent example of such merger-induced galaxy evolution.
Keywords
Cite
@article{arxiv.astro-ph/9504094,
title = {A Merger Origin for X-Structures in S0 Galaxies},
author = {Chris Mihos and Ian Walker and Lars Hernquist and Claudia Mendes de Oliviera and Mike Bolte},
journal= {arXiv preprint arXiv:astro-ph/9504094},
year = {2007}
}
Comments
6 pages of uuencoded compressed postscript. Accepted to ApJ Letters. 5 postscript figures available from http://www.ucolick.org/~hos/preprints/X/abstract.html