Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A refurbished convergent point method for finding moving groups in the
  Hipparcos Catalogue   The Hipparcos data allow a major step forward in the research of `moving
groups' in the Solar neighbourhood, as the common motion of group members
causes converging proper motions. Previous knowledge on these coherent
structures in velocity space has always been limited by the availability,
reliability, and accuracy of ground-based proper motion measurements.
  A refurbishment of Jones' convergent point method is presented which takes
full advantage of the quality of the Hipparcos data. The original
implementation of this method determines the maximum likelihood convergent
point on a grid on the sky and simultaneously selects group members from a
given set of stars with positions and proper motions. The refurbished procedure
takes into account the full covariance matrix of the Hipparcos measurements
instead of standard errors only, allows for internal motions of the stars, and
replaces the grid-based approach by a direct minimization. The method is tested
on Monte Carlo simulations of moving groups, and applied to the Hyades. Despite
the limited amount of data used by the convergent point method, the results for
stars in and around the cluster- centre region agree very well with those of
the recent comprehensive study by Perryman et al. (1998).

15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
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The categories of this paper are: dg-ga
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph
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The categories of this paper are: funct-an
10
The categories of this paper are: q-bio