Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Central Regions of M81   High angular resolution optical and near-infrared images are used to
investigate the central regions of the nearby Sb galaxy M81 (NGC3031). The
spectral-energy distribution of the circumnuclear region, which extends out to
1.5 arcsec (~ 24 pc if \mu_0 = 27.5) from the nucleus, can be modelled as a
combination of an old metal-rich population and emission from hot dust. Thermal
emission has been detected near other AGN, and simple models indicate that hot
dust can account for ~20% of the light in K within 0.5 arcsec of the M81
nucleus. An elongated structure with M_V ~ -7, which may be an area of active
star formation, is detected 0.45 arcsec from the nucleus. At distances in
excess of 1.5 arcsec from the nucleus the J-K color of the M81 bulge is not
significantly different from what is seen in M31. The HST data are also used to
search for bright globular clusters within 2kpc of the center of M81. The area
within 0.26 kpc of the M81 nucleus is largely devoid of bright globular
clusters, in agreement with what is seen in the central regions of the Galaxy
and M31. However, our survey indicates that there may be ~45 +/- 12 globular
cluster candidates with M_V \leq -7 within 2 kpc of the galaxy center, which is
consistent with what would be infered from the Milky-Way cluster system.

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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: q-fin
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The categories of this paper are: econ
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The categories of this paper are: nucl-th
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The categories of this paper are: cs
26
The categories of this paper are: bayes-an
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The categories of this paper are: quant-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg