A Genetic Approach to the History of the Magellanic Clouds

TL;DR

This paper uses a genetic algorithm combined with N-body hydrodynamic simulations to explore and identify possible orbital histories of the Magellanic Clouds around the Milky Way, matching observational data.

Contribution

It introduces a novel approach integrating genetic algorithms with hydrodynamic simulations to constrain the orbital history of the Magellanic Clouds.

Findings

Magellanic Clouds have orbited within the Milky Way's virial radius for at least 3 Gyr.

High concentration parameters (c≥20) are necessary for long-term orbital stability.

Mutual interactions between the Clouds reproduce observed features of the Magellanic System.

Abstract

The history of the Magellanic Clouds is investigated using N-body hydrodynamic simulations where the initial conditions are set by a genetic algorithm. This technique allows us to identify possible orbits for the Magellanic Clouds around the Milky Way, by directly comparing the simulations with observational constraints. We explore the parameter space of the interaction between the Magellanic Clouds and the Milky Way, considering as free parameters the proper motions of the Magellanic Clouds, the virial mass and the concentration parameter ($c$) of the Galactic dark matter halo. The best orbital scenarios presented here are considered with two different sets of parameters for the Milky Way disc and bulge components. The total circular velocity at the Sun's position ($\rm{R_{\odot}}=8.5\,\rm {kpc}$) is directly calculated from the rotation curve of the corresponding Galactic mass model. Our analysis suggests that the Magellanic Clouds have orbited inside the virial radius of the Milky Way for at least $3\,\rm{Gyr}$, even for low mass haloes. However, this is possible only with high values for the concentration parameter ($c\ge20$). In both orbital models presented here, the mutual interaction between the Magellanic Clouds is able to reproduce the observed features of the Magellanic System.