2000/06/23 by Thomas Zeltwanger, Neil F. Comins, Richard V. E. Lovelace
Physics and Astronomy · #Astronomy and Astrophysical Research #Center (category theory) #Dark matter #Dark matter halo #Galactic Center #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy rotation curve #Halo #Observable #Spiral galaxy #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/317124
20 text pages, 3 tables, 24 figures. A gzipped postscripped version with higher resolution figures can be downloaded from http://butch.umephy.maine.edu/kickers/Research/Sloshing/ . Accepted for publication in The Astrophysical Journal
arxiv created 2000/06/23 · openalex publication_date 2000/11/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Observations of lopsided spiral galaxies motivated us to explore whether the rapid passage of a companion galaxy could cause them. We examine whether the center of mass of the visible matter becomes displaced from the center of mass of the dark halo during the intruder's passage, thereby causing an asymmetric response and asymmetric structure. Two-dimensional N -body simulations indicate that this can happen. We also explore some consequences of this offset. These include the center of mass of the visible disk following a decaying orbit around the halo center of mass and the development of transient one-armed spirals that persist for up to six rotation periods. We then study the results of a variety of initial conditions based on such offsets. We report on the results of several runs in which we initially offset a disk from its halo's center of mass by an amount typical of the above interaction. In some runs the halo is free to move, while in others it is held fixed. We used three different mass distributions for the halo in these runs. We find that the disk's center of mass spiraled inward, creating a variety of observed or observable phenomena including one-armed spirals, massive clumps of particles, and counterrotating waves. The systems settle into relatively axisymmetric configurations. Whether or not the end states included a bar depended on a variety of initial conditions.