a Gaussian process for galaxy SEDs

Today Boris Leistedt and Michael Troxel (Manchester) came to Simons to hack on a proposal to change the latter years of DES observing strategy. Their argument is that a small amount of u-band imaging (currently DES does none) could have a huge impact on photometric redshifts (particularly bias), which, in turn, could have a huge impact on the accuracy of the convergence mapping and large-scale structure constraints. They spent the day doing complete end-to-end simulations of observing, photometry, data analysis, and parameter estimation. I shouldn't really blog this, because it isn't my research, but it is very impressive!/p>

On the side, Leistedt and I checked in on our project to build a generative model of galaxy photometry, in which the full family of possible spectral energy distributions would be latent variables. Leistedt had a great breakthrough: If the SEDs are drawn from a Gaussian process, then the observables are also drawn from a Gaussian process, because projection onto redshifted bandpasses is a linear operation! He has code that implements this and some toy problems that seem to work, so I am cautiously optimistic.

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