The maps of the microwave background radiation made by the WMAP satellite have been incredibly important in our understanding of the Universe. In most ways, the maps are amazingly consistent with the “standard model” of cosmology. In this model the Universe is made of mostly dark energy and dark matter, and the structure we see around us grew out of tiny density variations imprinted during a period of inflation.
But there are a few puzzles in the WMAP observations, mainly having to do with large-scale patterns in the maps. One of the puzzles is that large-angle correlations in the map are significantly weaker than expected. U.R. rising junior Austin Bourdon and I have written a paper analyzing some possible explanations for this puzzle. Our paper shows that a broad class of possible explanations can actually be ruled out, because they make the problem worse rather than better. The class of explanations we rule out includes some “exotic” models that have been proposed in the literature recently, but it also includes some much more mundane possibilities, such as various non-cosmological contaminants in the data.
In addition to posting it on the web, we’ve submitted the paper for publication in the journal Physical Review D. For any non-scientists who’ve read this far, the next step is that the paper will be sent out for review by experts, who will recommend for or against publication. In the mean time, most people who care about this subject will see it on the web archive.