what would you do with the PTF data?

Price-Whelan returned to NYU for a day (from distant Columbia, where he is now a grad student) to discuss methodologies for some of the projects he is thinking about with Palomar Transient Factory imaging data. There are lots of things possible; like most big projects, PTF creates more possible projects than there are collaborators to do them; this is why astrophysics is a great field! I argued that he should use the things we have been thinking about with respect to image combination and source detection to detect—and then analyze—the sources below the single-exposure detection limit. Any project PTF has done at high signal-to-noise can be done for far more sources additionally if you are willing to work at lower signal-to-noise (and at image level rather than catalog level).

Very Wide Field Surveys, day 3

There was a lot of transient discussion today, with talks about PTF and LSST. In Quinby's PTF talk, he showed Nick Konidaris's SED Machine which looks like a prototype for fast transient response. On Monday Strauss noted that LSST will issue 100,000 alerts per night, so a lot of thinking has to go on about how to deal with that. Transient argumentation continued into the semi-organized post-talk discussion over beer. Walkowicz's talk had some nice meta-discussion about the different choices you make for rare events vs common events, and within that, for known types of events vs unknown types.

For me the highlight talk today was by Dave Monet, talking about the future of astrometry. He very rightly pointed out that if Gaia and LSST work as planned, it is not just that they will dominate all of astrometry, but more importantly that they will do just about as well as it is possible to do, ever. That is, you could only beat them with insanely expensive things like new kinds of launch vehicles. So the key point for an astrometrist is how to be doing things that make sense in this context. I agree! Also, in response to a comment by me, he endorsed my (strongly held) position that the point of astrometry is not to produce long lists of numbers (positions, parallaxes, and proper motions); the point of astrometry is to answer high-level science questions, and with Gaia-scale data no-one knows really how to do that at the limit of what's in-principle possible. One of the most interesting things Monet said is that there is no real point in working on the global astrometric solution right now; there are no critical science questions that depend on it, and Gaia will break you.