pop-III stars won't do it

In the morning, I had a long discussion with Whitmore (Swinburne), Finkbeiner (CfA), and Schlafly (MPIA) about Whitmore's spectral calibration issues and the time variation of the fine-structure constant. In that discussion we ended up deciding (a) that the calibration issue is most likely caused by the arc illuminating the instrument differently from any star, and (b) that this outcome is the best possible outcome for Whitmore, because it can be modeled and calibrated out.

In the afternoon, at Hennawi (MPIA) group meeting, many interesting things transpired. One is that Girish Kulkarni (MPIA) can show that when you combine all the competing constraints, it is very unlikely that "population-III" (primordial-abundance) stars can be huge contributors to the cosmic radiation density; they can't provide a significant fraction of the necessary reionizing photons. Another is that we strongly encouraged Beta Lusso (MPIA) to perform her SED modeling on a large number of SDSS quasars, and fast, to smack down some not-so-good recent results!

All the while, Patel kept working on the Sloan Atlas and the statistics of quasar light curves.