Mathematics – Logic
Scientific paper
Jul 2001
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001phdt.........4b&link_type=abstract
PhD thesis, University of Liege
Mathematics
Logic
2
Scientific paper
The main objective of this project is to determine cosmological parameters (e.g., the Hubble parameter) and to measure the mass-to-light distribution in galaxies using gravitationally lensed quasars, which are among the most promising objects for measuring cosmological distances, hence the age of the Universe. We have been conducting long-term photometric monitoring programmes of multiply imaged quasars at The Nordic Optical Telescope (NOT, La Palma, Canary Islands) and at the 1.54m Danish telescope (La Silla, Chile). The data have been obtained on a weekly basis. Four time delays have been measured since the programme started in 1998, for the systems B1600+434, RXJ0911+0550, SBS1520+530 (observed at the NOT) and HE2149-2745 (observed at the 1.5m Danish). Microlensing effects have been detected in the lightcurves of three out of the four systems studied, indicating that such effects are common at optical wavelengths. We argue that spectrophotometric monitoring and multiband imaging are the best methods to distinguish microlensing effects from intrinsic variations in order (1) to improve the time delay measurement and hence the estimates of H0, and (2) to study the microlensing signal in order to constrain source size (quasar) and compact mass in the deflector (lensing galaxy). By combining the H0 values obtained in this project and the H0 estimates from other lensed systems in the literature a mean value H0=60+/-4 km/s/Mpc (95% confidence) is calculated, which is in agreement with estimates from other methods. The small uncertainty in this mean value confirms that this method may yield statistically accurate results in spite of the seemingly large systematic errors in the individual systems.
No associations
LandOfFree
Gravitational lensing as a tool for determining the age of the Universe does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Gravitational lensing as a tool for determining the age of the Universe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gravitational lensing as a tool for determining the age of the Universe will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1205390