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The Intrinsic Ellipticity of Spiral Disks

David R. Andersen·Matthew A. Bershady
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Abstract

We have measured the distribution of intrinsic ellipticities for a sample of 28 relatively face-on spiral disks. We combine H-alpha velocity fields and R and I-band images to determine differences between kinematic and photometric inclination and position angles, from which we estimate intrinsic ellipticities of galaxy disks. Our findings suggest disks have a log-normal distribution of ellipticities (mean epsilon =0.06) and span a range from epsilon= 0 (circular) to epsilon=0.2. We are also able to construct a tight Tully-Fisher relation for our face-on sample. We use this to assess the contribution of disk ellipticity on the observed Tully-Fisher scatter.

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David R. Andersen, Matthew A. Bershady. 2002-01-24. The Intrinsic Ellipticity of Spiral Disks. https://arxiv.org/abs/astro-ph/0201406

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