Stripe 82, day three

After a one-day hiatus, it was back to the Stripe 82 meeting in Princeton. Highlights today were too many to mention, but here are a few of my favorites:

Ivezic (UW) showed incredible tests of Stripe 82 calibration, including evidence for residuals as a function of pixel position, and camera column. He can even show that the filter curve shapes must be different for the different camera columns! He showed some incredible Hess diagrams showing the Sagittarius stream in different cuts; he can even measure its metallicity with photometry alone.

Smith (Shanghai) showed some of the Koposov (2013) time-domain catalog in S82 that replaces—and is more precise than—the Bramich (2008) catalog. He showed amazing overdensities of halo stars in velocity space; just incredible.

MacLeod (USNA) talked about quasar variability, comparing structure functions and damped random walks. She finds a huge range in amplitude and time-scale of the best-fit damped random walks but it was not clear what fraction of the variance in that distribution comes from noise (uncertainties) and what comes from a true underlying variance. That is a key question I would like to work on with Hernitshek (MPIA) and Mykytyn. She finds that variability decreases strongly with intrinsic luminosity, which is of great interest to Fadely and me.

Lang finished the meeting with a beautiful, pedagogical talk about how you optimally detect point sources in multi-epoch, multi-band imaging. He defined "optimal" to mean "saturating the Cramér–Rao bound. I love that! The results are beautiful, simple, and useful. Paper soon, I hope.

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