Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The star pile in Abell 545   Context:Struble (1988) found what appeared to be a cD halo without cD galaxy
in the center of the galaxy cluster Abell 545. This remarkable feature has been
passed almost unnoticed for nearly twenty years.
  Aims:Our goal is to review Struble's claim by providing a first (preliminary)
photometric and spectroscopic analysis of this ''star pile''.
  Methods:Based on archival VLT-images and long-slit spectra obtained with
Gemini-GMOS, we describe the photometric structure and measure the redshift of
the star pile and of the central galaxy.
  Results:The star pile is indeed associated with Abell 545. Its velocity is
higher by about 1300 km/s than that of the central object. The spectra indicate
an old, presumably metal-rich population. Its brightness profile is much
shallower than that of typical cD-galaxies.
  Conclusions:The formation history and the dynamical status of the star pile
remain elusive, until high S/N spectra and a dynamical analysis of the galaxy
cluster itself become available. We suggest that the star pile might provide an
interesting test of the Cold Dark Matter paradigm.

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The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
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The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
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The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys