Simulating the galactic system in interaction AM 2229-735 and the formation of its polar structure

TL;DR

This paper uses N-body+hydrodynamics simulations to model the formation of a polar ring galaxy through minor mergers, providing insights into galaxy evolution and dark matter distribution.

Contribution

It presents a detailed simulation-based study of polar ring galaxy formation via minor mergers, highlighting the dynamical conditions leading to polar structures.

Findings

Simulations reproduce observed interaction features like arms and bridges.

Identifies a stable, self-gravitating polar tidal stream as a merger remnant.

Suggests merger remnants can evolve into disk-like structures supporting dark matter studies.

Abstract

We study the formation of polar ring galaxies via minor mergers. We used N-body+hydrodynamics simulations to reproduce the dynamics of the observed system AM 2229-735 that is a minor merger whose interaction signals are those of a progenitor for a polar ring galaxy. We used the observational information of the system to get initial conditions for the orbit and numerical realisations of the galaxies to run the simulations. Our simulations reproduce the global characteristics of interaction observed in the system such as arms and a material bridge connecting the galaxies. As a merger remnant, we found a quasi-stable and self gravitating planar tidal stream with dark matter, stars and gas orbiting in a plane approximately perpendicular to the main galaxy disk leading in the future to a polar ring galaxy. We studied the dynamical conditions of the polar structure and found evidence suggesting that this kind of merger remnant can settle down in a disk-like structure with isothermal support, providing inspiring evidence about the process of formation of galactic disks and providing a potentially independent scenario to study the presence of dark matter in this kind of galaxies.