Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Imaging the AGN Torus in Cygnus   We present the first direct imaging of what may be the thick torus in the
active galactic nucleus (AGN) of the archetype powerful radio galaxy Cygnus A,
using the Jansky Very Large Array (VLA) at 18 GHz to 48 GHz, with a resolution
down to 45 mas. Such a torus has long been a key component of AGN models, but
direct imaging on the relevant physical scales in sources of extreme
(quasar-like) luminosities, remains scarce. An elongated structure,
perpendicular to the radio jets and centered on the core, is well resolved,
with a full length of $0.48"$ (528 pc), and a full width of $0.26"$ (286 pc).
The radio emission spectrum is consistent with optically thin free-free
emission. We present a toy model of a flaring torus, with a half-opening angle
for the poloidal region of $62^o$. The radio jets are oriented along the poles.
The observations require a clumpy gas distribution, with the free-free emission
dominated by clumps with densities $\ge 4000$ cm$^{-3}$

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The categories of this paper are: funct-an
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The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
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The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
9
The categories of this paper are: nlin
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The categories of this paper are: bayes-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: physics