Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Critical Lines in Gravitational Lenses and the Determination of
  Cosmological Parameters   We investigate the cosmological test recently proposed by B. Fort, Y. Mellier
and M. Dantel-Fort (FMD), where the observed location of the critical line in
gravitational lensing is used to determine the cosmological parameters,
$\Omega$ and $\lambda$. Applying this method to the cluster of galaxies
Cl0024+1654, FMD obtained a constraint on the cosmological constant, $\lambda >
0.6$, assuming the spatially flat universe. It plays a crucial role in this
method that the angular diameter distance-redshift relation depends on the
cosmological models through the cosmological parameters. First, using the
angular diameter distance in the Friedmann-Lemaitre- Robertson-Walker universe,
we show that one can hardly determine $\Omega$ by this method without the
assumption of the spatially flat universe. We also investigate the effect of
inhomogeneities of the universe by using the Dyer-Roeder angular diameter
distance. It is shown that the effect of inhomogeneities can become too large
to be ignored, particularly for a high density universe. As a result, this
method cannot be taken as a clear cosmological test to determine $\Omega$ and
$\lambda$, though it may provide a bound on $\Omega$ and $\lambda$. Moreover,
we mention the uncertainty of the determination of the velocity dispersion,
which is regarded as one of the most serious problems in this test.

26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess