GLOBAL SPIRAL ARMS FORMATION by NON-LINEAR INTERACTION of WAKELETS

Jun Kumamoto, Masafumi Noguchi

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

The formation and evolution of galactic spiral arms is not yet clearly understood despite much analytic and numerical work. Recently, the new idea has been proposed that local density enhancements (wakelets) arising in the galactic disk connect with each other and make global spiral arms. However, the understanding of this mechanism is not yet sufficient. We analyze the interaction of wakelets by using N-body simulations, including perturbing point masses, which are heavier than individual N-body particles and act as the seeds for wakelets. Our simulation facilitates a more straightforward interpretation of numerical results than previous works by putting a certain number of perturbers in a well-motivated configuration. We detected a clear sign of non-linear interaction between wakelets, which make global spiral arms by connecting two adjacent wakelets. We found that the wavenumber of the strongest non-linear interaction depends on galactic disk mass and shear rate. This dependence is consistent with the prediction of a swing amplification mechanism and other previous results. Our results unify previous results that were consistent with each other.

Original languageEnglish
Article number110
JournalAstrophysical Journal
Volume822
Issue number2
DOIs
Publication statusPublished - 2016 May 10

Keywords

  • galaxies: kinematics and dynamics
  • galaxies: spiral
  • methods: numerical

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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