Collaborative Research: The Last of FIRST: Completing Our View of the Radio Universe

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A ten-year program to use the world's most powerful radio telescope to provideFaint Images of the Radio Sky at Twenty-cm (FIRST) is nearing its goal of mapping theentire northern sky outside the Milky Way with a resolution and sensitivity that exceed previous surveys by a factor of fifty or more. Over three-quarters ofa million radio emitters have been detected to date, ranging from nearby activestars to the most distant quasars known. The images and source catalogs are allavailable on the World-Wide Web, and have been used to date by more thanthree hundred astronomers.The FIRST team is pursuing a number of major projects with this massive newdatabase. Matching the radio catalog to the near-infrared sources catalogedby the 2MASS survey, they have discovered a number of highly obscured quasars --objects emitting a thousand times the energy of the whole Milky Way from a tinyregion in a distant galaxy core that is so dust-ridden that no visiblelight escapes. Another major project is using the entire set of radio images to attempt todetermine the distribution of the mysterious dark matter in the Universe.Recognizing Einstein's dictum that mass bends light, they look for the slightdistortions in the shapes of distant radio galaxies caused by the passage oftheir radio waves through the mass distribution of the intervening space.While optical astronomers have been conducting such "weak lensing" experimentson patches of sky the size of the full moon and smaller, this research will study theclumpiness of the dark matter on scales ten to one hundred times larger,thus making a direct connection between the galaxy distribution in the local Universe and the fluctuations seen in the cosmic background radiation whichtells us the distribution of matter at the earliest times.