Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Infrared view of the obscured AGN environment in NGC 4945   NGC 4945 harbors one of the nearest active galactic nuclei (AGN), which
allows reaching high spatial resolution with the current observational
facilities. The Seyfert 2 nucleus is deeply obscured by an edge-on disk with
$A_V\sim14$, requiring infrared observations to study circumnuclear structures
and the interstellar medium. In this work, we present an imaging and longslit
spectroscopic study of the nuclear region with a spatial resolution of 6.5 pc,
based on Flamingos-2 (F2) and T-ReCS data taken at the Gemini South
observatory. We report sub-arcsecond photometric measurements of the nucleus in
$J$, $H$ and $K_{\rm s}$ filters, and at larger apertures. We do not detect
nuclear variability. The nuclear spectra confirm that even in $K$-band the AGN
emission-line features are completely obscured by dust. We detect a
circumnuclear disk in $K$-band as well as in the mid-infrared (MIR) $N$- and
$Q_{\rm a}$-bands, with a radial scale length of $\sim$120 pc. The disk shows
knots mostly in a ring-like arrangement that has been previously detected with
HST Pa $\alpha$ observations, indicating that these are deeply embedded,
massive young star clusters. We present here the spectrum of one of the
brightest and unresolved object (R$<5$pc), which we identify as a super star
cluster candidate with M$_{K_{\rm s}} -16.6\pm0.4$. For the circumnuclear
region, a detailed rotation curve allows to measure a nuclear mass of $M=(4.4
\pm 3)\times 10^{6} M_\odot$ within a radius of $\sim6.5$ pc. We also report
the detection of hot dust ($\sim 1000$ K) out to a nuclear distance of 80 pc
measured along the semi-major axis.

14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
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The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: solv-int
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The categories of this paper are: nlin
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The categories of this paper are: funct-an
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The categories of this paper are: q-bio
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The categories of this paper are: gr-qc
1
The categories of this paper are: cs
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-th