Gravitational Lensing, CFHTLS Cosmic Shear Survey & Angular Momentum In Disk Galaxies

The thesis is consisted of two parts: "The gravitational lensing "and "Theangular momentum problems in disk galaxy formation".Gravitational lensing is, as the General Relativity, that the gravitational fields offoreground objects deflect the light rays from background objects. Because thegravitational fields are independent of the states of foreground objects, gravitationallensing is becoming a very useful tool in modern astrophysics, especially forcosmology.In the first part of the thesis, the basic theory of gravitational lensing isintroduced, which includes strong lensing, weak lensing and microlensing,respectively, combined with their most recent observational results. With theimprovement of panoramic cameras and the validity of large sky survey areas, cosmicshear is now available to study the large scalar structure in the universe. Thedemonstrations of both theory and current observations of cosmic shear are presented.Especially, the introduction of CFHTLS survey, which is the ongoing project, isdescribed in detail including the data processing. Based on the current limitation dataof CFHTLS, the cosmic shear signals can be found and it can be predicted thatCFHTLS data will go one step further the other cosmic shears surveys in the future.In the second part of the thesis, the current paradigm of disk galaxy formation isbriefly reviewed and two main problems in disk galaxy formation models, i.e.,angular momentum catastrophe and mismatch of angular momentum problems, areintroduced respectively. The discussions of several possible mechanisms implementedfor them to solve the problems are also presented. A semi-analytic model of galaxy...