Self-perpetuating Spiral Arms in Disk Galaxies

Type Journal Article
Names Elena D'Onghia, Mark Vogelsberger, Lars Hernquist
Publication The Astrophysical Journal
Volume 766
Issue 1
Pages 34
Journal Abbreviation The Astrophysical Journal
Date March 1, 2013
DOI 10.1088/0004-637X/766/1/34
ISSN 0004-637X
Library Catalog
Abstract The causes of spiral structure in galaxies remain uncertain. Leaving aside the grand bisymmetric spirals with their own well-known complications, here we consider the possibility that multi-armed spiral features originate from density inhomogeneities orbiting within disks. Using high-resolution N-body simulations, we follow the motions of stars under the influence of gravity, and show that mass concentrations with properties similar to those of giant molecular clouds can induce the development of spiral arms through a process termed swing amplification. However, unlike in earlier work, we demonstrate that the eventual response of the disk can be highly non-linear, significantly modifying the formation and longevity of the resulting patterns. Contrary to expectations, ragged spiral structures can thus survive at least in a statistical sense long after the original perturbing influence has been removed.
Tags Methods: Numerical, galaxies: kinematics and dynamics, galaxies: spiral
UW-Madison Astronomy Home