pixel-level model

In the morning, to steady our thoughts, Foreman-Mackey, Barclay, and I wrote on the blackboard our model for the Kepler pixel-level data. This is the data-driven model we wrote up in the white paper. The idea is to fit pixels with other pixels, but taking as "other" pixels only those that are far enough away that they can't be being affected by the same star. These other pixels will share in spacecraft issues (like temperature and pointing issues) but not share in stellar variability or exoplanet transit effects, because different stars are independently variable. A key idea of our model, which Foreman-Mackey mocked up for our white paper, is that we avoid over-fitting the pixels by using a train-and-test framework, in which we "learn" the fit coefficients using data not near (in time) to the pixel value we are trying to predict (or de-trend).

In the evening, I started writing up this model and our results. We are all ready to write paper zero on this.