Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A GMRT multifrequency radio study of the isothermal core of the poor
  galaxy cluster AWM 4   We present a detailed radio morphological study and spectral analysis of the
wide-angle-tail radio source 4C +24.36 associated with the dominant galaxy in
the relaxed galaxy cluster AWM 4. Our study is based on new high sensitivity
GMRT observations at 235 MHz, 327 MHz and 610 MHz, and on literature and
archival data at other frequencies. We find that the source major axis is
likely oriented at a small angle with respect to the plane of the sky. The
wide-angle-tail morphology can be reasonably explained by adopting a simple
hydrodynamical model in which both ram pressure (driven by the motion of the
host galaxy) and buoyancy forces contribute to bend the radio structure. The
spectral index progressively steepens along the source major axis from $\alpha
\sim$0.3 in the region close to the radio nucleus to beyond 1.5 in the lobes.
The results of the analysis of the spectral index image allow us to derive an
estimate of the radiative age of the source of $\sim$ 160 Myr. The cluster
X-ray emitting gas has a relaxed morphology and short cooling time, but its
temperature profile is isothermal out to at least 160 kpc from the centre.
Therefore we seek evidence of energy ejection from the central AGN to prevent
catastrophic cooling. We find that the energy injected by 4C +24.36 in the form
of synchrotron luminosity during its lifetime is far less than the energy
required to maintain the high gas temperature in the core. We also find that it
is not possible for the central source to eject the requisite energy in the
intracluster gas in terms of the enthalpy of buoyant bubbles of relativistic
fluid, without creating discernible large cavities in the existing X-ray
XMM-Newton observations.

22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an