Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A measurement of the cosmological mass density from clustering in the
  2dF Galaxy Redshift Survey   The large-scale structure in the distribution of galaxies is thought to arise
from the gravitational instability of small fluctuations in the initial density
field of the universe. A key test of this hypothesis is that superclusters of
galaxies in the process of formation should generate systematic infall of other
galaxies. This would be evident in the pattern of recessional velocities,
causing an anisotropy in the inferred spatial clustering of galaxies. Here we
report a precise measurement of this clustering, using the redshifts of more
than 141,000 galaxies from the two-degree-field galaxy redshift survey. We
determine the parameter beta = Omega^{0.6}/b = 0.43 +- 0.07, where Omega is the
total mass-density parameter and b is a measure of the `bias' of the luminous
galaxies in the survey. Combined with the anisotropy of the cosmic microwave
background, our results favour a low-density universe with Omega approximately
0.3.

13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn