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Cosmic Microwave Background Analysis Tools
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| The Cosmic Microwave Background radiation provides a unique picture of the early universe. To realize its scientific potential NASA is leading an international effort to obtain precise measurements
of the CMB temperature and polarization from ground-based, balloon-borne, and satellite observatories. This proposal supports the development and distribution of the novel computational algorithms and implementations needed to plan observing strategies, simulate observations, and analyze data.
The CMB temperature power spectrum shape is a strong constraint on cosmologies. Its measurement requires a large area of sky observed at high resolution by many detectors at many frequencies. The
volume of such data makes their analysis a serious computational challenge; our MADCAP software can analyze maps with O(100,000) pixels but new data will give up to O(10,000,000) pixels,
requiring new approximate algorithms. New methods are also needed to analyze multiple channels to account for systematic effects from their cross-correlation and their different frequencies and beam
sizes.
CMB polarization provides a new window into the very early universe. Currently in the detection phase, the challenge is to observe a signal much fainter than the temperature anisotropies, requiring
well-planned observations and novel analyses. We will develop polarization extensions to our FORECAST and WOMBAT flight-planning tools, as well as first-generation simulation and analysis
tools.
To compare the CMB temperature or polarization power spectrum with cosmological models we search a 10-20 dimensional space of correlated parameters to get both the maximum likelihood parameter combination and the full likelihood contours. Since the parameter-likelihoods are
non-Gaussian formally we need to calculate them throughout this infinite space. In practice we must restrict ourselves to a finite sampling of a finite subset of the space: our goal is to codify and optimize the appoximations in this restriction. |
Bibliography
| | Making maps of the cosmic microwave background: The MAXIMA example
Stompor et al.; Physical Review, (2002) D 65, 0022003
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