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Дата индексирования: Tue Oct 2 02:43:14 2012
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Поисковые слова: m 87 jet
Constraints in the
0-
0 plane from gravitational lensing
Phillip Helbig et al.
Kapteyn Astronomical Institute, The Netherlands
Since the details of the gravitational lensing e ect depend on the
cosmological model, it o ers a means of determining the cosmolo-
gical parameters H0 , 0
and
0 by comparing expectations from
di erent cosmological models with observations. Advantages of
using gravitational lensing to learn about the cosmological model
include the fact that it is based on relatively well understood as-
trophysics and that it makes use of information from an interme-
diate redshift range, complementing tests which use information
primarily from the low-redshift (e.g. cosmic ows) or high-redshift
(e.g. cosmic microwave background uctuations) regimes.
I review simultaneous constraints on the cosmological parame-
ters 0
and
0 from gravitational lensing. (Constraints on H0
are discussed in a previous talk.) The emphasis is on system-
atic extragalactic surveys for strong gravitational lensing, mainly
the largest and best-de ned such survey, JVAS/CLASS. However,
other methods of constraining 0
and
0 using (mostly strong)
gravitational lensing are also discussed. After brie y reviewing
the basic theory and history of the subject, I present the cur-
rently available constraints and brie y (since this is covered in
later talks) touch on joint constraints with other cosmological
tests. Finally, I discuss systematic errors and prospects for the
future.
Co-authors: The JVAS/CLASS team
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