2004/04/21 by Dalia Chakrabarty
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2004.07930.x
published as Mon.Not.Roy.Astron.Soc. 352 (2004) 427 · 14 pages, 19 figures
arxiv created 2004/04/21 · openalex publication_date 2004/07/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
This paper describes test-particle simulations of the response of the outer parts of Galactic discs to barring and spiral structure. Simulations are conducted for cold Mestel discs and warm quasi-exponential discs with completely flat rotation curves, subjected to pure quadrupoles and logarithmic spirals. Even though the starting velocity distributions are smooth, the end-points of the bar simulations show bimodality and multipeaked structures at locations near the outer Lindblad resonance (OLR), although spirality can make this smoother. The growth of a bar may cause the disc isophotes to become boxy at the OLR, as stars accumulate particularly along the minor axis. The growth of a bar is also accompanied by substantial heating of the disc stars near the OLR. For the growth of a 1010-M⊙ bar, the radial velocity dispersion is typically quadrupled for initially cold discs (initial σu∼ 10 km s−1), and typically doubled for discs with final σu∼ 45 km s−1. Simulations performed of the growth and dissolution of bars give very similar results, demonstrating that the heat once given to disc stars is very difficult to remove.