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Neutral hydrogen sub-structure in the Galactic Halo outside the solar circle

Published online by Cambridge University Press:  17 September 2012

L. Dedes  and
P.M.W. Kalberla
L. Dedes
Affiliation:
Auf dem Hügel 71, 53121 Bonn, Germany
P.M.W. Kalberla
Affiliation:
Auf dem Hügel 71, 53121 Bonn, Germany
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Abstract

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.

Type
Research Article
Information
European Astronomical Society Publications Series , Volume 56: The Role of the Disk-Halo Interaction in Galaxy Evolution: Outflow vs. Infall? , 2012 , pp. 209 - 212
Copyright
© EAS, EDP Sciences, 2012

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