Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Probing the History of Cluster Assembly by Intracluster Planetary
  Nebulae   We describe the results and the current status of our program to search for
intracluster planetary nebulae (ICPNe) in the Virgo and the Coma clusters of
galaxies. For the Virgo cluster, ICPNe candidates were detected with narrow
band imaging combined with broad band imaging. The use of two narrow band
filters for H$\alpha$ and [O III] lines tuned for the cluster redshift enabled
us to detect secure ICPNe candidates. Kinematics of the detected ICPNe confirm
that the Virgo cluster is in a highly unrelaxed state. In order to detect ICPNe
in the Coma cluster, which is more than five times more distant than the Virgo
cluster, we devised a multi-slit imaging spectroscopy technique and
successfully detected 35 secure ICPNe candidates for the first time in this
cluster. We have found a hint that the Coma cluster is currently in the midst
of a subcluster merger.

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The categories of this paper are: chem-ph
1
The categories of this paper are: cs
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
3
The categories of this paper are: physics