Simulations of tidally induced spiral arms

TL;DR

This study uses N-body simulations to explore how tidal interactions in galaxy clusters can trigger, wind up, and dissipate grand design spiral arms in Milky Way-sized galaxies over billions of years.

Contribution

It demonstrates that tidal interactions can produce transient, recurrent spiral arms that are approximately logarithmic, providing insight into their dynamic nature.

Findings

Spiral arms are triggered by pericenter passages.

Arms wind up and dissipate over time.

Spiral arms are dynamic, transient, and recurrent.

Abstract

The origin of grand design spiral structure in galaxies is still under debate but one of promising scenarios involves tidal interactions. We use N-body simulations to study the evolution of a Milky Way-size galaxy in a Virgo-like cluster. The galaxy is placed on a typical eccentric orbit and evolved for 10 Gyr. We find that grand design spiral arms are triggered by pericenter passages and later on they wind up and dissipate. The arms formed in the simulations are approximately logarithmic, but are also dynamic, transient and recurrent.