Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Emission line galaxies in clusters   At the present epoch, clusters of galaxies are known to be a hostile
environment for emission-line galaxies, which are more commonly found in low
density regions outside of clusters. In contrast, going to higher redshifts the
population of emission-line galaxies in clusters becomes progressively more
conspicuous, and large numbers of star-forming late-type galaxies are observed.
I present an overview of the observational findings and the theoretical
expectations regarding the evolution of emission-line galaxies in dense
environments, discussing the properties of these galaxies and the current
evidence for environmental influences on their evolution.

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The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin