week_5_assignmnts.md

1. 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.
2. Complete assignment 2 from last week, if not already.
3. Work with the notebook "Intro to lens modeling with lenstornomy.ipynb". Fit the lensing system given to you (that matches your team number and order) last week in this folder. The fitting is done well when you get a reduced $\chi^2$ very close to 1.
4. Understand everything that is being done in the notebook. (It’s fine to not fully understand kwargs_likelihood and kwargs_numerics at this point.)
5. Run an MCMC after the PSO. Ensure that the MCMC chain has converged. Obtain the best-fit values and uncertainties for $\theta_{\rm E}$ and $\gamma$.