To appear in "Gravitational Lensing:
a unique tool for cosmology", ASP conference series, 2003,
eds. D. Valls-Gabaud & J.-P. Kneib
astro-ph/0304497
For a PDF version of the article, click
here.
For a Postscript version of the article, click
here.
QUASAR LENSING: THE OBSERVER'S POINT OF VIEW
F. Courbin
Institut d'Astrophysique et de Géophysique,
Université de
Liège,
Allée du 6 août 17, Bat B5C, Liège 1, Belgium
Abstract. The determination of the Hubble parameter H0 is probably one
of the
most important applications of quasar lensing. The method, based on
the measurement of the so-called "time-delay" between the lensed
images of distant sources, e.g., quasars, and on detailed mass
modeling of the potential well responsible for the multiple images,
yields an accuracy at least comparable with other techniques and that
can be improved further with high precision observations, as can be
obtained with intrumentation of constantly increasing quality. The
basics of the "time-delay" method are described, and the emphasis is
put on the observational constraints available to the astrophysicist
in order to implement the method and to derive an accurate value for
H0, independent of any standard candle or any strong prior on the
other cosmological parameters.
Table of Contents
WHY OBSERVING LENSED QUASARS ?
- FIRST DISCOVERIES AND SEARCHES
- A Few Lucky Cases
- Systematic Searches and the Magnification Bias
- LENSED QUASARS AND H0
- The Time-delay Method
- Constraints and Uncertainties
- The Mass Model and Degeneracies
- PG 1115+080: A CLEAN QUADRUPLE
- Redshifts
- Time-delays and Temporal Sampling
- Modeling and Influence of the Astrometry
- HST Imaging: the Quasar Host Galaxy
- Yet Further Constraints: Spectroscopy
- H0 with PG 1115+080
- MASS PRODUCTION OF TIME-DELAYS: H0 WITH
OTHER LENSES
- REFERENCES
