LOFAR to Search for First Stars and Galaxies

More than 20,000 radio antennas will soon connect over the Internet to scan largely unexplored radio frequencies, hunting for the first stars and galaxies and potentially signals of extraterrestrial intelligence. The Low Frequency Array (LOFAR) will consist of banks of antennas in 48 stations in the Netherlands and elsewhere in Europe, all hooked up by fiber optic cables. Currently 16,000 of LOFAR’s antennas and 41 of its stations are up, and the array will be completed by the middle of this year. All told, LOFAR will have a resolution equivalent to a telescope 620 miles (1,000 kilometers) in diameter. According to George Heald of ASTRON since LOFAR is so large, it can scan large parts of the heavens, its first all-sky survey, which started January 9, can sweep across the entire northern sky twice in just 45 days. LOFAR is also very fast, capable of measuring events only five-billionths of a second long. In addition, the fact that LOFAR is essentially many different radio telescopes knit together means it can run, say, three different science projects simultaneously. The array is designed to monitor low-frequency radio waves, a largely unexplored part of radiation from the sky. One critical source of these radio emissions are extremely feeble signals from the cold hydrogen gas that dominated the cosmos during the so-called dark ages of the universe. As stars eventually came into being, they would have left scars on this hydrogen, and by analyzing how the radio signals from this gas changed over time, scientists can therefore learn much about how the first galaxies came to be. LOFAR will also scan for artificial radio emissions as part of the search for extraterrestrial intelligence (SETI). Low-frequency radio waves are also emitted around intensely powerful cosmic objects such as black holes, and investigating these could help scientists better understand the inner workings of these ferocious systems.

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