The Collisions of HVCs with a Magnetized Gaseous Galactic Disk

Abstract

We present two-dimensional MHD numerical simulations for the interaction of high-velocity clouds with both magnetic and non-magnetic Galactic thick gaseous disks. For the magnetic models, the initial magnetic field is oriented parallel to the disk, and we consider two different field topologies (with and without tension effects): parallel and perpendicular to the plane of motion of the clouds. The impinging clouds move in oblique trajectories and fall toward the central disk with different initial velocities. The $B$-field lines are distorted and compressed during the collision, increasing the field pressure and tension. This prevents the cloud material from penetrating into the disk, and can even transform a high-velocity inflow into an outflow, moving away from the disk. The perturbation creates a complex, turbulent, pattern of MHD waves that are able to traverse the disk of the Galaxy, and induce oscillations on both sides of the plane. Thus, the magnetic field efficiently transmits the perturbation over a large volume, but also acts like a shield that inhibits the mass exchange between the halo and the disk. For the non-magnetized cases, we also uncover some novel features: the evolution of the shocked layer generates a tail that oscillates, creating vorticity and turbulent flows along its trajectory.

Accepted for publication in ApJ, 22 text pages with 8 figures

References in corpus (5)

• Extraplanar Dust in the Edge-On Spiral NGC 891
• The MHD Kelvin-Helmholtz Instability II: The Roles of Weak and Oblique Fields in Planar Flows
• Superbubbles in magnetized interstellar media --- Blowout or confinement ? ---
• The Collisions of HVCs with a Magnetized Gaseous Galactic Disk
• The Thermal Pressure of the Hot Interstellar Medium derived from Cloud Shadows in the Extreme Ultraviolet

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