Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dynamical segregation of galaxies in groups and clusters   We have performed a systematic analysis of the dynamics of different galaxy
populations in galaxy groups from the 2dFGRS. For this purpose we have combined
all the groups into a single system, where velocities v and radius r are
expressed adimensionally. We have used several methods to compare the
distributions of relative velocities of galaxies with respect to the group
centre for samples selected according to their spectral type (as defined by
Madgwick et al., 2002), bj band luminosity and B-R colour index. We have found
strong segregation effects: spectral type I objects show a statistically
narrower velocity distribution than that of galaxies with a substantial star
formation activity (type II-IV). Similarly, the same behavior is observed for
galaxies with colour index B-R>1 compared to galaxies with B-R<1. Bright
(Mb<-19) and faint (Mb>-19) galaxies show the same segregation. It is not
important once the sample is restricted to a given spectral type. These effects
are particularly important in the central region (Rp<Rvirial/2) and do not have
a strong dependence on the mass of the parent group. These trends show a strong
correlation between the dynamics of galaxies in groups and star formation rate
reflected both by spectral type and by colour index.

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The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
2
The categories of this paper are: math
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The categories of this paper are: q-alg
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The categories of this paper are: alg-geom