High‐Latitude Hiin the Low Surface Brightness Galaxy UGC 7321

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Abstract
From the analysis of sensitive H I 21 cm line observations, we find evidence for vertically extended H I emission ( 2.4 kpc) in the edge-on, low surface brightness spiral galaxy UGC 7321. Three-dimensional modeling suggests that the H I disk of UGC 7321 is both warped and flared, but that neither effect can fully reproduce the spatial distribution and kinematics of the highest z-height gas. We are able to model the high-latitude emission as an additional H I component in the form of a thick disk or halo with a FWHM of ~3.3 kpc. We find tentative evidence that the vertically extended gas declines in rotational velocity as a function of z, although we are unable to completely rule out models with constant V . In spite of the low star formation rate of UGC 7321, energy from supernovae may be sufficient to sustain this high-latitude gas. However, alternative origins for this material, such as slow, sustained infall, cannot yet be excluded.
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