Morphological classification of nearby galaxies based on asymmetry and luminosity concentration |
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| Authors: | M Yagi Y Nakamura M Doi K Shimasaku S Okamura |
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| Institution: | Department of Physics, Durham University, South Road, Durham DH1 3LE;Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA;Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH |
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| Abstract: | We investigate the behaviour of the asymmetry parameter A as a morphological parameter using a 'volume-limited' sample of 349 galaxies (distance ≤25 Mpc, MV ≤?18.5 mag) and a larger magnitude-limited sample of 707 nearby galaxies. We confirm the correlation of A with morphological type. The late-type galaxies (Sdm, Sm and Im) have larger A than early-type galaxies, and they tend to have larger A than spiral galaxies. We investigate the usefulness of the A versus concentration index C in diagram as a tool for the regular–irregular and early–late classification. The diagram is not very useful to the regular versus late-type irregular classification, as inferred previously, but it is found to be useful to the early–late classification. |
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| Keywords: | galaxies: active galaxies: individual: Markarian 6 galaxies: Seyfert X-rays: galaxies |
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