Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cooling flows, central galaxy--cluster alignments, X-ray absorption and
  dust   We present the analysis of pointed ROSAT PSPC observations of five of the
most luminous, intermediate redshift ($0.1 < z < 0.15$) clusters of galaxies
detected in the ROSAT All-Sky Survey. The PSPC data are combined with optical
CCD images and spectra to examine the relationship between clusters and their
central cluster galaxies (CCGs). Abell 1068, Abell 1361 and Abell 1664 contain
three of the most optically line-luminous CCGs known. The PSPC X-ray data show
that these galaxies lie at the centres of massive (200 -- 400 solar masses per
year) cooling flows. The alignment between CCGs and their host clusters has
been investigated. For those clusters with cooling flows, the position angles
of the X-ray emission from the clusters and the optical emission from the CCGs
agrees within 5 degrees. For the one probable non-cooling flow cluster in the
sample, Abell 2208, the alignment is significantly poorer. We examine the
evidence for intrinsic X-ray absorption in the clusters. The X-ray spectra for
Abell 1068 and Abell 1664 show that the cooling flows in these clusters are
intrinsically absorbed by equivalent hydrogen column densities $\geq 10^{21}
atom cm$^{-2}$. The optical spectra of the CCGs in these clusters exhibit
substantial intrinsic reddening, at levels consistent with the X-ray absorption
results if standard dust to gas ratios are assumed.

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The categories of this paper are: eess
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The categories of this paper are: mtrl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg
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The categories of this paper are: gr-qc
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-th
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The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
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The categories of this paper are: nucl-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: cond-mat