Issue |
A&A
Volume 387, Number 3, June I 2002
|
|
---|---|---|
Page(s) | 788 - 803 | |
Section | Astrophysical processes | |
DOI | https://doi.org/10.1051/0004-6361:20020448 | |
Published online | 17 May 2002 |
Constraining the cosmological parameters using strong lensing
Laboratoire d'Astrophysique, Observatoire Midi-Pyrénées, 14 Av. E. Belin, 31400 Toulouse, France
Corresponding author: G. Golse, ghislain.golse@ast.obs-mip.fr
Received:
16
March
2001
Accepted:
18
March
2002
We investigate the potential of using strong lensing
clusters to constrain the cosmological parameters and
. The existence of a multiple image system with
known redshift allows, for a given (
,
)
cosmology, absolute calibration of the total mass deduced from
lens modelling. Recent Hubble Space Telescope (HST)
observations of galaxy clusters reveal a large number of multiple
images, which are predicted to be at different redshifts. If it
is possible to measure spectroscopically the redshifts of
many multiple images then one can in principle constrain
(
,
) through ratios of angular diameter
distances, independently of any external assumptions. For
a regular/relaxed cluster observed by HST with 3 multiple
image systems, each with different spectroscopic redshifts, we
show by analytic calculation that the following uncertainties can
be expected:
,
or
,
for the two most popular world models. Numerical tests on
simulated data confirm these good constraints, even in the case
of more realistic cluster potentials, such as bimodal clusters,
or when including perturbations by galaxies. To investigate the
sensitivity of the method to different mass profiles, we also
use an analytic “pseudo-elliptical” Navarro et al. profile in the simulations. These constraints can be
improved if more than 3 multiple images with spectroscopic
redshifts are observed, or by combining the results from
different clusters. Some prospects on the determination of the
cosmological parameters with gravitational lensing are
given.
Key words: cosmology: cosmological parameters / gravitational lensing / cosmology: dark matter / galaxies: clusters: general
© ESO, 2002
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