EAS Publications Series
Volume 56, 2012The Role of the Disk-Halo Interaction in Galaxy Evolution: Outflow vs. Infall?
|Page(s)||209 - 212|
|Section||Evidence for a Disk-Halo Connection in Galaxies|
|Published online||17 September 2012|
Miguel A. de Avillez (ed)
EAS Publications Series, 56 (2012) 209–212
Neutral hydrogen sub-structure in the Galactic Halo outside the solar circle
Auf dem Hügel 71, 53121 Bonn, Germany
21-cm studies of the Galactic extra-planar gas layer can help us understand the origin of the gaseous Galactic halo and its interaction with the Milky Way disk. The 100-m Effelsberg radio telescope was utilized to detect and analyze a population of Hi halo clouds belonging to this layer, at Galactocentric radii R > 8.5kpc, following Galactic rotation. This sample of clouds has similar properties to the population detected by Lockman with the GBT at R < 8.5kpc. High resolution follow-up observations resolve them into a number of small, dense, cold arc-minute sized Hi cores. Their study provides evidence for a thermal equilibrium with the extended warmer envelopes. Single dish observations with the 300-m Arecibo telescope disclosed a sample of Hi clouds with similar properties. A power spectrum analysis of the Arecibo maps probes the characteristics of turbulence as a dominant physical process in the halo region.
© EAS, EDP Sciences, 2012