The study of the nature and evolution of the universe, that is, the science of cosmology, has undergone a remarkable revolution in the last ten years. At the heart of that revolution are new experimental efforts that are yielding immense amounts of data. Cosmology has been transformed from a data-starved state to data-swamped in less than a decade. This data is providing unprecedented views of the very early universe and how it evolved from a fraction of a second after the big-bang to its present state. Some of the most compelling problems in fundamental physics have either arisen or sharpened because of cosmological discoveries.
Matt Abroe, Graduate Student Researcher
Julian Borrill, Lawrence Berkeley National Laboratory, Berkeley, California
Ken Ganga, College de France, Paris, France
J.-C. Hamilton, College de France, Paris, France
Brad Johnson, Graduate Student Researcher
Radek Stompor, Center for Particle Astrophysics, University of California, Berkeley, California
The cosmic microwave background radiation (CMB) is a relic of the big bang. The rediation travels through the universe practically undisturbed. The CMB was first discovered in 1965 and immediately recognized as one of the most important cornerstones of the big bang model for the evolution of the universe. Observing the CMB today is analogous to taking a snap-shot of the universe at its earliest observable age.
The CMB is extremely uniform in intensity over the entire sky. In 1992, the DMR instrument aboard NASA's COBE satellite discovered intensity fluctuations across the sky. This anisotropy is widely believed to encode matter density variations in the early universe that later collapsed gravitationally to form the galaxies and clusters of galaxies observed today.
The COBE-DMR discovery initiated an intense scientific program whose goal was a complete mapping of the CMB anisotropy over the entire sky with a resolution of few arcminutes, because detailed understanding of the CMB anisotropy is an extremely powerful tool to constrain models of the early universe, understand structure formation, and provide cosmological parameters to better than 1%. Those include the total matter density in the universe, the amount of negative energy density, the amount of baryons, and hence, the amount of dark matter, and the expansion parameter.
This research is participating in three collaborations that are mapping the CMB anisotropy-the MAXIMA and Archeops balloon borne experiments and the Planck Surveyor satellite. MAXIMA is a balloon borne program funded by NASA and the NSF and in collaboration with the University of California at Berkeley. It has already been launched twice and collected large quantities of high-quality data. Archeops is a balloon borne program conducted by a subset of the international consortium of scientists who are building ESA's Planck satellite. The payload has already been launched once, mapped a large part of the sky, and will be launched at least twice within the next three years.
The nature of the analysis of the data generated by these experimental programs requires linear algebra operation on very large matrices, on the order of 50,000 x 50,000 elements each. Currently, only parallelized supercomputers and high-performance algorithms can handle these data sets. These researchers have installed and compiled the necessary software packages and prepared them for the data analysis. The first results of the work are appearing during 2000, working on data from MAXIMA.
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