Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Galaxy Pairs in the 2dFGRS II. Effects of interactions on star formation
  in groups and clusters   We analyse the effects of galaxy interactions on star formation in groups and
clusters of galaxies with virial masses in the range $10^{13} - 10 ^{15}
M_{\odot}$. We find a trend for galaxy-galaxy interactions to be less efficient
in triggering star formation in high density regions in comparison with
galaxies with no close companion.
  However, we obtain the same relative projected distance and relative radial
velocity thresholds for the triggering of significant star formation activity
($r_p \sim 25 h^{-1} $ kpc and $\Delta V \sim 100 {\rm km s^{-1}}$) as found in
the field. Thus, the nature of star formation driven by galaxy interactions is
nearly independent of environment, although there is a general lower level of
star formation activity in massive systems. The above results reflect, on one
hand, the local nature of star formation induced by tidal interactions and, on
the other, the role played by the internal properties of galaxies. By using a
2dFGRS mock catalog we estimate the contamination by spurious pairs finding
that the statistics are cleary dominated by real pairs. We also found the
behaviour of the trends to be robust against the use of more restrictive
relative velocity thresholds.(Abridged)

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The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics