Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The detection of molecular gas in the central galaxies of cooling-flow
  clusters   We present the detections of CO line emission in the central galaxy of
sixteen extreme cooling flow clusters using the IRAM 30m and the JCMT 15m.
These detections of CO(1-0), CO(2-1), CO(3-2) and CO(4-3) are consistent with
the presence of a substantial mass of warm molecular gas (10^9-11.5Mo) within
50kpc radius of the central galaxy. We present limits on thirteen other
galaxies in similarly extreme cooling flow clusters. These results are
consistent with the presence of a massive starburst in the central galaxy which
warms a population of cold gas clouds producing both optical and NIR emission
lines and significant CO line emission. Curiously, our CO detections are
restricted to the lower radio power central galaxies. These are the first
detections of molecular gas in a cooling flow other than NGC1275 in the Perseus
cluster. As four of our targets have firm limits on their dust mass from SCUBA
and the rest have crude limits from IRAS, we can calculate gas-to-dust ratios.
Simple analysis indicates that the best secondary indicatorof molecular gas is
optical line luminosity. We review the implications of these results and the
prospects for observations in the near future.

2
The categories of this paper are: math
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
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The categories of this paper are: cond-mat
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The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an