AAS 206th Meeting, 29 May - 2 June 2005
Session 38 Interstellar Medium, H II Regions and Molecular Clouds
Poster, Wednesday, 10:00am-7:00pm, Thursday, 9:20am-2:00pm, June 1, 2005, Ballroom A

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[38.03] Kinematics of the Diffuse Ionized Gas in NGC 891

G. H. Heald, R. J. Rand (University of New Mexico), R. A. Benjamin (University of Wisconsin - Whitewater), M. A. Bershady (University of Wisconsin - Madison)

In some external edge-on spirals, the azimuthal velocity of halo gas is observed to decrease with height above the midplane (z). This effect has been observed in both the neutral and ionized components of halos. Models of the disk-halo interaction which consider the effects of moving gas out of the disk and into the halo predict such a velocity gradient as a consequence of the conservation of angular momentum. In order to observationally test the predictions of such models, high spectral resolution emission line data with two-dimensional coverage are required to first estimate the form of the radial density profile in the halo, and subsequently extract the azimuthal velocities as a function of z. We present high spectral resolution WIYN SparsePak observations of the diffuse ionized gas (DIG) in NGC 891. Preliminary results of an analysis of the azimuthal velocity field will also be summarized. This work is part of an ongoing project to investigate the vertical azimuthal velocity gradient of the ionized halo gas in a select sample of edge-on spirals with a range of DIG halo morphology.

This material is based on work partially supported by the National Science Foundation under Grant No. AST 99-86113.

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Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.