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arXiv · astro-ph/0404374

Dominant galaxies in 2dF groups

B. Kelm·P. Focardi
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Abstract

We investigate whether the spectral-type of a locally dominant (most luminous) galaxy can be used to select sets of galaxies that are physically associated (groups). We assume that passive dominants trace a group-like potential, and SF-dominants a field-like environment. The group sample includes 988 groups selected in the 2dFGRS applying a maximum magnitude difference criterion. We find that the average number of passive galaxies associated to a dominant is larger when the dominant is passive, a result supporting our assumption that galaxy associations around a passive dominant are reliable groups. Finally we show that, to reduce the contamination by unbound galaxy associations (SF-dominant), a >=3 passive-members criterion is more efficient than a >=6 all-members criterion.

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B. Kelm, P. Focardi. 2004-04-20. Dominant galaxies in 2dF groups. https://doi.org/10.1017/s1743921304000997

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