Publication Abstracts

Russell and Roberts 1992

Russell, W.S., and W.W. Roberts, Jr., 1992: On the distribution of pitch angles in external galactic spirals NGC 1232 and NGC 5457. Astrophys. J., 398, 94-104, doi:10.1086/171839.

A numerical method, originally developed to analyze the morphology of global and local structure in prototype galaxies, is modified for analyzing observed disk-shaped galaxies. Two digitized spiral galaxies NGC 1232 and NGC 5457 with varying degrees of contrast between arm and interarm regions are analyzed. A synergism of partitioning methods and a geometric mean least-squares regression algorithm serves to isolate local arm segments, spurs, feathers, and secondary features and to measure their pitch angles and lengths. The global arms are actually highly disjointed, with arm segments frequently revealing pitch angles between 30° and 50°, certainly greater than those of the parent arms. Prominent spurs tend to exhibit a much greater pitch angle. The automated mathematical algorithm is shown to have negligible numerical biasing and could be applied to any number of spiral galaxies manifesting flocculent structure, either prototype or observed, and could possibly be used as a tool for classification of multiple-armed-type galaxies.

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BibTeX Citation

@article{ru08000d,
  author={Russell, W. S. and Roberts, Jr., W. W.},
  title={On the distribution of pitch angles in external galactic spirals NGC 1232 and NGC 5457},
  year={1992},
  journal={Astrophys. J.},
  volume={398},
  pages={94--104},
  doi={10.1086/171839},
}

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RIS Citation

TY  - JOUR
ID  - ru08000d
AU  - Russell, W. S.
AU  - Roberts, W. W., Jr.
PY  - 1992
TI  - On the distribution of pitch angles in external galactic spirals NGC 1232 and NGC 5457
JA  - Astrophys. J.
VL  - 398
SP  - 94
EP  - 104
DO  - 10.1086/171839
ER  -

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