SDSS meeting, day 1

I am at the SDSS meeting at Fermilab. I spoke about how we are going about looking at the huge galaxies—galaxies comparable to or larger than an individual SDSS field. We have to build mosaics; building mosaics is non-trivial if you want to preserve all the information in the data. For me, this is part of our Gunn Atlas project.

There were incredibly impressive talks from the Supernovae team (working with the multiple epochs in the SDSS Southern Stripe that my reader knows well). They are taking systematics much more seiously than I have ever seen before. This is a good thing about getting particle experimentalists involved in precision cosmology. The scariest systematic (presented by Kessler of Fermilab) was a near-degeneracy between dust absorption, the intrinsic scatter in supernovae colors, and the world model.

Related to that, Holtzman (NMSU) gave a remarkable talk about how they do the time-variable supernova photometry; it involves making a complete fit to all of the pixels in all of the images at all epochs! This is not unlike the proper-motion stuff I was doing this summer, but much, much more sophisticated.

There were remarkable talks all day; two others that stood out were about clear detections of the MgII-absorber–galaxy cross-correlation function by Nestor (Cambridge) and the scale and success and potential of the galaxyzoo.com project by Thomas (Portsmouth). This latter project has some similarities in spirit to Astrometry.net, although they have much less technology under the hood.