Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High-resolution X-ray imaging and spectroscopy of the core of NGC 4945
  with XMM-Newton and Chandra   We utilize the complimentary capabilities of XMM-Newton and Chandra, to
conduct a detailed imaging and spectral study of the nearby galaxy NGC 4945
focussing on its nucleus and immediate surroundings (within ~1 kpc of the
nucleus). A complex morphology is revealed including a predominantly hard, but
partially resolved, nuclear source plus a spectrally soft, conically shaped
X-ray "plume", which extends 30" (500 pc) to the northwest. In NGC 4945 our
direct view of the active galactic nucleus (AGN) is blocked below ~10 keV by
extremely heavy line-of-sight absorption and the observed X-ray spectrum is
dominated by multi-temperature thermal emission associated with the nuclear
starburst and the X-ray plume. Nevertheless the signature of the AGN is present
in the form of a neutral Compton reflection component and a 6.4 keV fluorescent
iron Ka line. We conjecture that the site of the continuum reprocessing is the
far wall of a highly inclined molecular torus, a geometry which is consistent
with the presence of H2O megamaser emission in this source. The soft spectrum
(~0.6 keV) and limb-brightened appearance of the X-ray plume suggest an
interpretation in terms of a mass-loaded superwind emanating from the nuclear
starburst.

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The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
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The categories of this paper are: funct-an
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The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
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The categories of this paper are: adap-org
1
The categories of this paper are: cs
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The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th