On the Formation of Elliptical Rings in Disk Galaxies

TL;DR

This paper uses N-body simulations to study how elliptical rings form in disk galaxies during collisions, revealing a linear relationship between ring eccentricity and galaxy inclination.

Contribution

It introduces an analytic formula linking ring eccentricity with inclination angle and time, aiding interpretation of galactic merger histories.

Findings

Eccentricity of rings is linearly proportional to inclination angle.

Derived an analytic formula for ring eccentricity as a function of time and inclination.

Simulation results confirm the linear relationship between inclination and eccentricity.

Abstract

N-body simulations of galactic collisions are employed to investigate the formation of elliptical rings in disk galaxies. The relative inclination between disk and dwarf galaxies is studied with a fine step of five degrees. It is confirmed that the eccentricity of elliptical ring is linearly proportional to the inclination angle. Deriving from the simulational results, an analytic formula which expresses the eccentricity as a function of time and inclination angle is obtained. This formula shall be useful for the interpretations of the observations of ring systems, and therefore reveals the merging histories of galaxies.