Modeling Merging Galaxies using MINGA - Improving Restricted N-body by Dynamical Friction

TL;DR

This paper enhances the restricted N-body simulation method by incorporating dynamical friction, enabling more accurate modeling of galaxy mergers and orbital decay, validated through extensive comparison with self-consistent simulations.

Contribution

The authors introduce a dynamical friction extension to the restricted N-body method, improving its ability to simulate galaxy mergers with realistic orbital decay.

Findings

Reliable reproduction of orbital decay in galaxy mergers

Effective modeling of tidal features for mass ratios up to 1/3

Validated against over 250,000 simulations

Abstract

Modeling interacting galaxies to reproduce observed systems is still a challenge due to the extended parameter space (among other problems). Orbit and basic galaxy parameters can be tackled by fast simulation techniques like the restricted N-body method, applied in the fundamental work by Toomre & Toomre (1972). This approach allows today for the study of millions of models in a short time. One difficulty for the classical restricted N-body method is the missing orbital decay, not allowing for galaxy mergers. Here we present an extension of the restricted N-body method including dynamical friction. This treatment has been developed by a quantitative comparison with a set of self-consistent merger simulations. By varying the dynamical friction (formalism, strength and direction), we selected the best-fitting parameters for a set of more than 250000 simulations. We show that our treatment reliably reproduces the orbital decay and tidal features of merging disk galaxies for mass ratios up to q=1/3 between host and satellite. We implemented this technique into our genetic algorithm based modeling code MINGA and present first results.