Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: ICM Signatures from Multiple Outbursts in the Galaxy Group NGC 5813: A
  Window to AGN Feedback   We present results from Chandra observations of NGC 5813, the dominant
central galaxy in a nearby galaxy group. We focus on three main results. 1) The
diffuse gas shows clear signatures from three distinct outbursts of the central
AGN, with three pairs of roughly collinear cavities. The inner two cavity pairs
are associated with unambiguous elliptical shock fronts, with Mach numbers
M~1.7 and M~1.5 for the inner and outer shocks, respectively. 2) The mean power
of the two most recent outbursts differs by a factor of six, indicating that
the mean jet power varies over long (~10^7 yr) time scales. 3) The heating from
the shocks alone is sufficient to balance radiative cooling of the gas within
at least the central 10 kpc, allowing feedback to operate isotropically at
small radii.

28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
18
The categories of this paper are: econ
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
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The categories of this paper are: q-fin
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin