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M. Dorris, V. Petrosian (Stanford U.)
In many analyses of galaxy count data for the purpose of determination of their morphological distribution and cosmological evolution, the observed samples are treated as if only magnitude limited and well-determined by the parameters of the luminosity function. While more recent surveys have considered additional selection effects or more complex statistics, for a more exact analysis we must consider both the multivariate nature of the objects and complexities of observational selection effects.
We discuss the effects of flux, surface brightness, and size detection limits using a bivariate distribution of luminosity and surface brightness for disks and spirals. Using this combination of limits and bivariate statistic, and including the effects of K-correction, we derive the expected variation of the relative occurrence of disks versus ellipsoids in different samples. Comparison with observation determines the relative rate of cosmological evolution of different morphological types and can provide hints of the formation process of these types. Results obtained from 2dF, HDF and SDSS samples will be presented.
If you would like more information about this abstract, please follow the link to http://www.stanford.edu/people/dorris/research/bivariate.html. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.
The author(s) of this abstract have provided an email address for comments about the abstract: dorris@stanford.edu
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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.