Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: X-ray Cavities and Cooling Flows   Recent data have radically altered the X-ray perspective on cooling flow
clusters. X-ray spectra show that very little of the hot intracluster medium is
cooler than about 1 keV, despite having short cooling times. In an increasing
number of cooling flow clusters, the lobes of a central radio source are found
to have created cavities in the hot gas. Generally, the cavities are not
overpressured relative to the intracluster gas, but act as buoyant bubbles of
radio emitting plasma that drive circulation as they rise, mixing and heating
the intracluster gas. All this points to the radio source, i.e. an active
galactic nucleus, as the heat source that prevents gas from cooling to low
temperatures. However, heating due to bubbles alone seems to be insufficient,
so the energetics of cooling flows remain obscure. We briefly review the data
and theory supporting this view and discuss the energetics of cooling flows.

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The categories of this paper are: plasm-ph
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The categories of this paper are: patt-sol
19
The categories of this paper are: eess
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The categories of this paper are: atom-ph
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The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
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The categories of this paper are: alg-geom
1
The categories of this paper are: cs
16
The categories of this paper are: stat
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The categories of this paper are: mtrl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
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The categories of this paper are: q-fin