Classification of galaxies on CCD frames
Morphological classifications of 231 galaxies in and near the Virgo and Ursa Major clusters are reported which show that luminosity classification techniques (LCTs) can be used to determine the luminosities of spiral galaxies with an accuracy of about 0.7 mag on CCD frames. The observations in the d...
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Veröffentlicht in: | The Astrophysical journal 1990-08, Vol.359 (1), p.4-14 |
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Sprache: | eng |
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Zusammenfassung: | Morphological classifications of 231 galaxies in and near the Virgo and Ursa Major clusters are reported which show that luminosity classification techniques (LCTs) can be used to determine the luminosities of spiral galaxies with an accuracy of about 0.7 mag on CCD frames. The observations in the direction of the Virgo Cluster confirm the assignment of some galaxies to the background field, strongly confirming that the large dispersion in the Tully-Fisher relation for Virgo galaxies is at least partly due to contamination of the Virgo core sample by background galaxies. LCTs yield a distance of 15.3 + 2.6 or - 2.2 Mpc for the spiral and irregular galaxies associated with the core of the Virgo Cluster proper. The Ursa Major and Virgo cluster distances are found to be the same. A class of galaxies with fuzzy, anemic outer structure and active star formation in their cores is found to be common in Virgo but rare in the Ursa Major Cluster. 31 refs. |
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ISSN: | 0004-637X 1538-4357 |
DOI: | 10.1086/169027 |