Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Centaurus Group and the Outer Halo of NGC 5128: Are they Dynamically
  Connected?   NGC 5128, a giant elliptical galaxy only $\sim 4$ Mpc away, is the dominant
member of a galaxy group of over 80 probable members. The Centaurus group
provides an excellent sample for a kinematic comparison between the halo of NGC
5128 and its surrounding satellite galaxies. A new study, presented here, shows
no kinematic difference in rotation amplitude, rotation axis, and velocity
dispersion between the halo of NGC 5128, determined from over $\sim340$ of its
globular clusters, and those of the Centaurus group as a whole. These results
suggest NGC 5128 could be behaving in part as the inner component to the galaxy
group, and could have begun as a large initial seed galaxy, gradually built up
by minor mergers and satellite accretions, consistent with simple cold dark
matter models. The mass and mass-to-light ratios in the B-band, corrected for
projection effects, are determined to be $(1.3\pm0.5) \times 10^{12}$
M$_{\sun}$ and $52\pm22$ M$_{\sun}$/L$_{\sun}$ for NGC 5128 out to a
galactocentric radius of 45 kpc, and $(9.2\pm3.0) \times 10^{12}$ M$_{\sun}$
and $153\pm50$ M$_{\sun}$/L$_{\sun}$ for the Centaurus group, consistent with
previous studies.

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The categories of this paper are: cs
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The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
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The categories of this paper are: q-fin
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The categories of this paper are: math
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The categories of this paper are: quant-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-th
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
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The categories of this paper are: funct-an
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The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ