Query : 2005A&A...443..435W

2005A&A...443..435W - Astronomy and Astrophysics, volume 443, 435-449 (2005/11-4)

Red-sequence galaxies with young stars and dust: the cluster Abell 901/902 seen with COMBO-17.


Abstract (from CDS):

We report the discovery of a rich component of dusty star-forming galaxies contaminating the red-sequence in the supercluster system comprising Abell 901a, 901b and A902 at redshift ∼0.17. These galaxies do not fit into the colour-density relation, because their preferred habitat is different from that of regular red-sequence galaxies, which are typically dust-poor, old and passively evolving. The dusty red galaxies prefer the medium-density outskirts of clusters while being rare in both the low-density field and the high-density cluster cores. This new result is based on the information content in the medium-band photometry of the COMBO-17 survey. The photo-z accuracy of the ∼800 brightest cluster galaxies is <0.01 and of the order of the velocity dispersion of the cluster. This enables us to select a rich and clean cluster sample, in which we can trace age-sensitive and dust-sensitive spectral features independently with the detailed medium-band SED data. We find the red colour of the dusty galaxies to be a result of dust extinction combined with relatively old stellar ages. We speculate that the dusty red galaxies could either be a product of minor mergers between established old red cluster galaxies with infalling blue field galaxies, or mark a period in the internal transformation of blue field galaxies into red cluster galaxies, which is triggered by the environmental influences experienced during cluster infall.

Abstract Copyright:

Journal keyword(s): surveys - techniques: photometric - methods: data analysis - galaxies: clusters: general - galaxies: evolution

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
1 ZwCl 0024+1652 ClG 00 26 36.0 +17 08 36     18.35     ~ 614 1
2 HD 86014 PM* 09 55 39.8123610792 -09 50 16.859171760   10.098 9.653 9.1 9.44 F6V 12 0
3 ACO 901 ClG 09 55 56.9256 -10 01 46.519           ~ 105 1
4 IRAS 09540-0946 Mi* 09 56 32.9070916848 -10 01 18.048000180           M8III 11 0
5 ACO 902 ClG 09 56 33.600 -10 09 13.10           ~ 59 1

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