AAS 198th Meeting, June 2001
Session 8. Normal Galaxies: Stellar Pops, ISM and Dynamics
Display, Monday, June 4, 2001, 9:20am-6:30pm, Exhibit Hall

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[8.12] HST Observations of Fractal Dust Structure in the Central Kiloparsec of Spiral Galaxies

D.M. Elmegreen (Vassar Coll.), B.G. Elmegreen (IBM Watson Res. Ctr.), K.S. Eberwein (Vassar Coll.)

We examined the dust morphology in the central kiloparsec of 20 normal and active galaxies in order to look for pressure-driven waves that are predicted to dominate over density waves when gaseous self-gravity is weak. Such acoustic waves may provide a mechanism for the transport of material into active centers of nonbarred galaxies. Our sample includes nonbarred Seyfert 1, Seyfert 2, and LINER galaxies, plus normal galaxies of the same early Hubble types. These galaxies represent about one-fourth of the galaxies examined; the others showed primarily a two-arm dust structure in the nuclear regions. The size distribution of the dust structures in these 20 galaxies was examined with unsharp masks and Gaussian smoothing. The distribution function was found to be a power law with about the same slope in each galaxy, suggesting universal fractal structure reminiscent of pressure-driven turbulence.

We gratefully acknowledge an HST Cycle 10 archival grant, HST-AR-09197.01

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