MHD simulations of ram pressure stripping of a disk galaxy

TL;DR

This study uses 3D MHD simulations to explore how magnetic fields influence ram pressure stripping of disk galaxies, revealing effects on disk structure, gas inflow, and star formation potential.

Contribution

It is the first to simulate face-on RPS of a disk galaxy including magnetic fields, showing their impact on gas dynamics and morphology.

Findings

Magnetic fields cause the disk to become flared.

Oblique shocks form at the interaction interface, compressing gas.

Magnetic fields lead to smoother gas morphology compared to hydro cases.

Abstract

The removal of the interstellar medium (ISM) of disk galaxies through ram pressure stripping (RPS) has been extensively studied in numerous simulations. Nevertheless, the role of magnetic fields (MF) on the gas dynamics in this process has been hardly studied, although the MF influence on the large-scale disk structure is well established. With this in mind, we present a 3D magnetohydrodynamic (MHD) simulation of face-on RPS of a disk galaxy to study the impact of the galactic MF in the gas stripping. The main effect of including a galactic MF is a flared disk. When the intracluster medium (ICM) wind hits this flared disk, oblique shocks are produced at the interaction interface, where the ISM is compressed, generating a gas inflow from large radii towards the central regions of the galaxy. This inflow is observed for $\sim 150$ Myr and may supply the central parts of the galaxy with material for star formation while the outskirts of the disk are being stripped of gas, thus the oblique shocks can induce and enhance the star formation in the remaining disk. We also observed that the MF alters the shape and structure of the swept gas, giving a smooth appearance in the magnetized case and clumpier and filamentary-like morphology in the hydro case. Finally, we estimated the truncation radius expected for our models using the Gunn-Gott criterion and found that is in agreement with the simulations.