In the morning Grant Christopher (NYU) successfully defended his PhD on TeV cosmic rays from Milagro. By cleverly using the Moon's shadow, he can take a spectrum of the cosmic rays, and measure the relative contributions of different species. By this method he has the world's best limit on the anti-proton flux at TeV energies. Lots more can be done; it is a beautiful technique, using the Moon as a kind of inverse pinhole camera!
In the afternoon Adi Zolotov defended her PhD, on the stellar halos of galaxies in realistic simulations. She shows that stellar halos generically have multiple chemically distinct populations, and some of the stars in the halo were born in the host galaxy and then flung out. She also generally finds that there is radial mixing (as there is in the disk) in the halo. At the same time, she makes robust testable predictions, even though she has to live with pragmatic and therefore uncertain simulations: She finds the aspects of the simulations that are most reliable. It is a great piece of work, and although I am her advisor on paper, Willman is her real advisor; it was also a pleasure to have her here for the defense.
With all these thesis defenses, including those of my two great students Bovy and Zolotov, it has been a great week. Have I mentioned recently that I love my job?