lecture5

Lecture 5: Gravitational lensing formalism 3 - observables and degeneracies

Reading in preparation for lecture 5: Schneider & Sluse (2013)

Homework (due Wednesday February 12th at lecture:

• Familiarize yourself with the Singular Isothermal Sphere (SIS) and Elliptical power-law (EPL) mass model. Read the documentation in lenstronomy.
• Familiarize yourself with the design of lenstronomy by running the starting guide notebook
• Check out the notebook "Fitting a lens model by hand.ipynb" and try to develop an intuition for how different parameters involved in a lensing system can change the look of the system. Create a perfectly round Einstein ring by appropriately choosing the slider values in the section “Simulating a lens system.” In the section “Demonstration of lens modeling by tuning parameters by hand”, try to achieve a reduced $\chi^2$ as close to 1 as possible. If you want to look at the right answers, they’re given here.