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Paper: Color Gradients of Dwarf Galaxies in the Coma Cluster
Volume: 421, Galaxies in Isolation: Exploring Nature Versus Nurture
Page: 246
Authors: den Brok, M.; Peletier, R. F.; Kleijn, G. V.; Valentijn, E. A.; Comas, M. B.; Carter, D.
Abstract: Internal color gradients in galaxies probe a variation in stellar populations as a function of radius. Galaxies that have formed through monolithic collapse, should have a steep metallicity gradient (Carlberg 1984), whereas galaxy merging is expected to wash out gradients (White 1980). Studies of elliptical galaxies (Peletier et al. 1990) have found primarily negative gradients that have been interpreted as mainly due to metallicity (Faber 1977).

We are extending these studies to dwarf galaxies in one of the richest environments of the local Universe, using high resolution and high sensitivity data from the Coma ACS Survey (Carter et al. 2008). Our goal is to test galaxy formation schemes for dwarf galaxies and quantify the influence of the environment on their evolution.

We use galphot (Jorgensen, Franx and Kjærgaard 1992) to measure the azimuthally averaged surface brightness in the to a common resolution convolved F814W and F475W filter bands for a sample of likely Coma members (Trentham et al. 2009). The dwarf galaxies in our sample show primarily blue nuclei, whereas the central colors of ellipticals are reddened because of dust. After excluding the central parts of these galaxies, we find surprisingly weak but slightly negative logarithmic color gradients independent of host galaxy magnitude.
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