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arXiv · astro-ph/0301463

The Surface Brightness and Colour-Magnitude Relations for Fornax Cluster Galaxies

A. M. Karick·M. J. Drinkwater·M. D. Gregg
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Abstract

We present BVI photometry of 190 galaxies in the central region of the Fornax Cluster observed with the Michigan Curtis Schmidt Telescope. The cluster members exhibit a strong surface brightness-magnitude relation in our data: both giant and dwarf ellipticals decrease in surface brightness as luminosity decreases. However the surface brightness-magnitude relation is no longer a reliable method for determining cluster membership at surface brightnesses fainter than 22 mag/sq.arcsec. The newly discovered ultra-compact dwarf galaxies (UCDs) lie well off the normal surface brightness-magnitude relation. We present the colour-magnitude relation for a sample of 113 cluster galaxies as a function of morphological type. The UCDs also lie off the locus of this relation. Their mean V-I colours are redder than dwarf galaxies of similar luminosity, but similar to those of globular clusters associated with NGC 1399. The location of the UCDs on both surface brightness and colour-magnitude plots supports the hypothesis that they are the remnants of tidally stripped nucleated dwarf elliptical galaxies.

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A. M. Karick, M. J. Drinkwater, M. D. Gregg. 2003-05-19. The Surface Brightness and Colour-Magnitude Relations for Fornax Cluster Galaxies. https://doi.org/10.1046/j.1365-8711.2003.06813.x

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