2003/05/21 by L. D. Matthews, Lynn T. Matthews, Kenneth Wood · 4 citations
Physics and Astronomy · #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/376602
published as Astrophys.J. 593 (2003) 721-732 · to appear in the August 20 Astrophysical Journal; 17 pages; version with full resolution figures available at http://cfa-www.harvard.edu/~lmatthew/
arxiv created 2003/05/21 · openalex publication_date 2003/08/11 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
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.