The collisions of high-velocity clouds with the galactic halo

TL;DR

This study models plasma waves generated by high-velocity clouds colliding with galactic halo gas, revealing their potential role in heating the halo and advancing understanding of galaxy halo dynamics.

Contribution

It provides a numerical analysis of plasma wave generation during HVC collisions and explores their physical properties and implications for halo heating.

Findings

Plasma waves are generated during HVC collisions with the galactic halo.

These waves can contribute to heating the ambient halo gas.

The study offers insights into the dynamics of HVC interactions with galactic media.

Abstract

Spiral galaxies are surrounded by a widely distributed hot coronal gas and seem to be fed by infalling clouds of neutral hydrogen gas with low metallicity and high velocities. We numerically study plasma waves produced by the collisions of these high-velocity clouds (HVCs) with the hot halo gas and with the gaseous disk. In particular, we tackle two problems numerically: 1) collisions of HVCs with the galactic halo gas and 2) the dispersion relations to obtain the phase and group velocities of plasma waves from the equations of plasma motion as well as further important physical characteristics such as magnetic tension force, gas pressure, etc. The obtained results allow us to understand the nature of MHD waves produced during the collisions in galactic media and lead to the suggestion that these waves can heat the ambient halo gas. These calculations are aiming at leading to a better understanding of dynamics and interaction of HVCs with the galactic halo and of the importance of MHD waves as a heating process of the halo gas.