after SDSS-III

On the train to and from Baltimore, I worked on typing up everything Fergus has done so far in modeling data from the P1640 spectroscopic coronograph. It is all words, and one heck of a lot of them, but I somehow feel like equations will be even more confusing.

I spent the full work day at JHU in a meeting about the projects that are being assembled to make use of the SDSS 2.5-m Telescope and its spectrographs in the 2014 and beyond period. It was a great meeting, chaired by AS3 (yes "After SDSS-III") Director Mike Blanton (congratulations!). So much was conveyed and discussed in one intense day, I could never properly summarize it. But here are a few highlights for me:

Blanton reviewed the status and budget; with the current imagined scope the budget really can't be less than 40M USD; at full scope and a southern hemisphere companion instrument it gets close to 60M USD. That's not cheap, so we have to create great things. Bundy overviewed the MaNGA project to perform full IFU spectroscopy on 10,000 nearby galaxies to do lots of science and create a massive legacy data set. Drory convinced me that fiber bundles—at least mass-produced fiber bundles— are not a solved problem and represent considerable project risk. During Wake's talk about sample selection a brief battle (started by Drory) broke out about selecting on purely observational properties relative to inferred physical properties. It was a great discussion and hit many philosophical issues of the responsibility for responsible hypothesis testing between observers and theorists and so on. Of course I scare-quoted the above words because the distinction is not totally sound.

Kneib talked about the eBOSS project to continue measuring the baryon acoustic feature at many redshifts with many probes. His thinking about all this has led to a number of enormous proposals (my name on some of them) going in to large telescopes to do enormous imaging projects for selection and weak lensing. I have found a great audience for Holmes, Rix, and my paper on self-calibration. He also showed that he can easily find emission line galaxies at a wide range of redshifts in SDSS and measure their redshifts spectroscopically with the BOSS spectrograph. He showed a galaxy at redshift 1.6 measured with BOSS. Newman showed that WISE does an amazing job of selecting redshift-unity luminous red galaxies. It can select them confidently at magnitudes fainter than we can confidently get spectroscopic reshifts! Crazy! Green overviewed the ambitious TDSS, which plans—I love this— to take a spectrum of every (in some well defined sense) variable object in the PanSTARRS imaging footprint. Awesome!

I got some reactions out of the crowd on three points: I argued that spectrophotometry for the IFU survey is fundamentally different than it was for the previous three SDSS surveys. The arguments for this are subtle and I should write them down carefully. I argued that every MaNGA cartridge should be different by design to maximize efficiency. That was shouted down because of complexity; I don't in fact disagree. I argued that even if you can't get a redshift for a lot of the faint LRGs, they still might be useful for constraining the baryon acoustic feature. That just got laughs!