Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: X-ray Properties of the Abell 644 Cluster of Galaxies   We use new ASCA observations and archival ROSAT Position Sensitive
Proportional Counter (PSPC) data to determine the X-ray spectral properties of
the intracluster gas in Abell 644. From the overall spectrum, we determine the
average gas temperature to be 8.64 (+0.67,-0.56) keV, and an abundance of 0.32
(+/-0.04) $Z_{\odot}$. The global ASCA and ROSAT spectra imply a cooling rate
of 214 (+100,-91) $M_{\odot}$ yr$^{-1}$. The PSPC X-ray surface brightness
profile and the ASCA data suggest a somewhat higher cooling rate. We determine
the gravitational mass and gas mass as a function of radius. The total
gravitating mass within 1.2 Mpc is $6.2\times10^{14}$ $M_{\odot}$, of which 20%
is in the form of hot gas. There is a region of elevated temperature 1.5-5
arcmin to the west of the cluster center. The south-southwest region of the
cluster also shows excess emission in the ROSAT PSPC X-ray image, aligned with
the major axis of the optical cD galaxy in the center of the cluster. We argue
that the cluster is undergoing or has recently undergone a minor merger. The
combination of a fairly strong cooling flow and evidence for a merger make this
cluster an interesting case to test the disruption of cooling flow in mergers.

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The categories of this paper are: chao-dyn
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The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
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The categories of this paper are: stat
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
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The categories of this paper are: funct-an
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The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
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The categories of this paper are: solv-int
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The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
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The categories of this paper are: plasm-ph