EAS Publications Series
Volume 56, 2012The Role of the Disk-Halo Interaction in Galaxy Evolution: Outflow vs. Infall?
|Page(s)||201 - 204|
|Section||Evidence for a Disk-Halo Connection in Galaxies|
|Published online||17 September 2012|
Miguel A. de Avillez (ed)
EAS Publications Series, 56 (2012) 201–204
Global Properties Of The Extra-Planar Hi Gas In The Milky Way
Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
We derive the 3-D volume density distribution for the Milky Way H i gas out to a galactocentric distance R = 60 kpc and separate the extra-planar component from the disk gas. The main part of the Milky Way H i distribution is significantly warped but shows a coherent structure out to R ∼ 35 kpc. Extra-planar gas can be distinguished from this disk component. From profile wings observed at the Galactic poles we find evidence for a highly turbulent H i distribution. For a velocity dispersion of 74 km s−1 the turbulent pressure gradient of this extra-planar gas is on average in balance with the gravitational forces. Such a component with a radial scale length of 7.5 kpc describes also the H i gas at the outskirts (40 < R < 60 kpc). About 10% of the H i gas is in this state. This component resembles the anomalous gas discovered in some galaxies.
© EAS, EDP Sciences, 2012