VizieR Online Data Catalog: Bulge and disc colours of ETG in Coma (Head+, 2014)
Abstract
We consider internal bulge and/or disc colour gradients by allowing component sizes to vary between bands. Gradients are required for 30 percent of analysis sample galaxies. Bulge half-light radii are found to be uncorrelated with galaxy luminosity (Re~1kpc, n~2) for all but the brightest galaxies (Mg<-20.5). The S0 discs are brighter (at fixed size, or smaller at fixed luminosity) than those of star-forming spirals. A similar colour-magnitude relation is found for both bulges and discs. The global red sequence for S0s in Coma hence results from a combination of both component trends. We measure an average bulge - disc colour difference of 0.09+/-0.01mag in g-i, and 0.16+/-0.01mag in u-g. Using simple stellar population models, bulges are either ~2-3 times older, or ~2 times more metal rich than discs. The trend towards bluer global S0 colours observed further from Coma's core is driven by a significant correlation in disc colour with cluster-centric radius. An equivalent trend is detected in bulge colours at a marginal significance level. Our results therefore favour environment-mediated mechanisms of disc fading as the dominant factor in S0 formation.
(2 data files).- Publication:
-
VizieR Online Data Catalog
- Pub Date:
- July 2015
- Bibcode:
- 2015yCat..74401690H
- Keywords:
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- Clusters: galaxy;
- Galaxies: photometry;
- Photometry: SDSS;
- Morphology