Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Microwave background anisotropies due to non-linear structures in open
  and Lambda universes   A new method arising from a gauge-theoretic approach to general relativity is
applied to the formation of clusters in an expanding universe. The three
cosmological models (Omega_0=1, Omega_Lambda=0), (Omega_0=0.3,
Omega_Lambda=0.7), (Omega_0=0.3, Omega_Lambda=0) are considered, which extends
our previous application (Lasenby et al. 1999
-"http://xxx.soton.ac.uk/abs/astro-ph/9810123"-, Dabrowski et al. 1999
-"http://xxx.soton.ac.uk/abs/astro-ph/9810149"-). A simple initial velocity and
density perturbation of finite extent is imposed at the epoch z=1000 and we
investigate the subsequent evolution of the density and velocity fields for
clusters observed at redshifts z=1, z=2 and z=3. Photon geodesics and redshifts
are also calculated so that the Cosmic Microwave Background (CMB) anisotropies
due to collapsing clusters can be estimated. We find that the central CMB
temperature decrement is slightly stronger and extends to larger angular scales
in the non-zero Omega_Lambda case. This effect is strongly enhanced in the open
case. Gravitational lensing effects are also considered and we apply our model
to the reported microwave decrement observed towards the quasar pair PC
1643+4631 A & B.

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The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
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The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
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The categories of this paper are: stat
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The categories of this paper are: hep-lat