EAS Publications Series
Volume 56, 2012The Role of the Disk-Halo Interaction in Galaxy Evolution: Outflow vs. Infall?
|Page(s)||299 - 304|
|Section||The Active Disk-Halo Connection: Infall vs. Outflows|
|Published online||17 September 2012|
Miguel A. de Avillez (ed)
EAS Publications Series, 56 (2012) 299–304
On the Kinematics of Extraplanar Gas
Dept. of Physics, University of Wisconsin-Whitewater, 800 West Main St, Whitewater, WI 53190, USA
A review of the observational constraints and theoretical models of extra-planar rotation (lagging halos) is presented. It is becoming clear that lagging halos, with vertical gradients in rotation speeds ranging from dvΘ/dz = −8to − 60km s−1kpc−1, are a ubiquitous phenomenon. The observational data so far does not allow one to say definitively whether this number changes with radius or with vertical height in a galaxy, but it is pointed out that such measurements, along with constraints on the presence of radial flows, will provide a crucial test that may allow one to distinguish between the different physical models that produce lagging halos. Some challenges in kinematically distinguishing between Galactic circulation and extragalactic accretion are also discussed.
© EAS, EDP Sciences, 2012