A Mushroom-shaped Structure from the Impact of a Cloud with the Galactic Disk
Abstract
We propose that the mushroom-shaped structure of the Galactic worm GW 123.4--1.5 is created by a cloud collision with the Galactic gas disk. A hydrodynamic simulation shows that a mushroom-shaped structure is created after the cloud crosses the Galactic midplane. The lifetime of the mushroom-shaped structure is of order the dynamical time scale of the disk, \sim 10^7 years. We find that the velocities across the cap of the mushroom-shaped structure in the simulation are consistent with the observed values. The simulation also predicts a structure on the opposite side of the Galactic plane which is created by the Kelvin-Helmholtz instability after the cloud passes through the disk.
Keywords
Cite
@article{arxiv.astro-ph/0405165,
title = {A Mushroom-shaped Structure from the Impact of a Cloud with the Galactic Disk},
author = {Takahiro Kudoh and Shantanu Basu},
journal= {arXiv preprint arXiv:astro-ph/0405165},
year = {2009}
}
Comments
6 pages, 5 figures, accepted for publication in A&A, color figures and movies at http://www.astro.uwo.ca/~kudoh/mushroom/