An Investigation into the mp Scale of Volume I of Zwicky et al.'s
Catalog of Galaxies and Clusters of Galaxies
Christopher Ke-shih Young and Zheng-yi Shao, PASA, 18 (2), in press.
Next Section: Introduction
Total Magnitudes of Virgo Galaxies. II.
An Investigation into the mp Scale of Volume I of Zwicky et al.'s
Catalog of Galaxies and Clusters of Galaxies
Christopher Ke-shih Young1,2,3 and Zheng-yi Shao1,2,4
1 Shanghai Astronomical Observatory, Chinese Academy of Sciences,80 Nandan Road, Xuhui District, Shanghai 200030, China
cky@center.shao.ac.cn / zyshao@center.shao.ac.cn
2 National Astronomical Observatories, Chinese Academy of Sciences,
20A Datun Road, Chaoyang District, Beijing 100012, China
3 Department of Astrophysics and Optics, School of Physics,
the University of New South Wales, Sydney 2052, Australia
cky@bat.phys.unsw.edu.au
4 School of Physics and Astronomy, University of Nottingham,
University Park, Nottingham NG7 2RD, Great Britain
Zhengyi.Shao@nottingham.ac.uk
Abstract:
, the mp values listed correspond very closely (with a scatter of only 0.16 mag.) to blue magnitudes measured to the 
isophote. If mp values need to be used as estimates of total blue magnitude the scatter is 0.27 mag. over the same range in Bt and the mean offset is
mp-Bt=0.28 mag. However, a serious scale error at the bright end causes both the isophotal and total luminosities of galaxies brighter than 
to be severely under-estimated. At the faint end there also appears to be a significant scale error. This causes galaxy luminosities to be seriously over-estimated faintward of
. We demonstrate that this is a real effect based on a detailed galaxy-by-galaxy study of the catalogue's completeness down to Bt=17.0. The catalogue is found only to be complete to
whilst its degree of incompleteness is found to be relatively constant at the 30% level over the range
. Most of the missing objects are found to be elliptical galaxies and so late-type objects are over-represented at the faint end.
Keywords: catalogues - galaxies: clusters: individual: Virgo - galaxies: fundamental parameters - galaxies: photometry
- Introduction
- Our galaxy samples and CGCG completeness
- Isophotal magnitudes
- Estimating Bt from mp
- Estimating mp from Bt
- Conclusions
- Acknowledgements
- References
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б© Copyright Astronomical Society of Australia 1997