Paper detail

CMB Analysis

We describe the subject of Cosmic Microwave Background (CMB) analysis - its past, present and future. The theory of Gaussian primary anisotropies, those arising from linear physics operating in the early Universe, is in reasonably good shape so the focus has shifted to the statistical pipeline which confronts the data with the theory: mapping, filtering, comparing, cleaning, compressing, forecasting, estimating. There have been many algorithmic advances in the analysis pipeline in recent years, but still more are needed for the forecasts of high precision cosmic parameter estimation to be realized. For secondary anisotropies, those arising once nonlinearity develops, the computational state of the art currently needs effort in all the areas: the Sunyaev-Zeldovich effect, inhomogeneous reionization, gravitational lensing, the Rees-Sciama effect, dusty galaxies. We use the Sunyaev-Zeldovich example to illustrate the issues. The direct interface with observations for these non-Gaussian signals is much more complex than for Gaussian primary anisotropies, and even more so for the statistically inhomogeneous Galactic foregrounds. Because all the signals are superimposed, the separation of components inevitably complicates primary CMB analyses as well.