Hydrogen at z~25: the Large Aperture Experiment to Detect the Dark Age

Lincoln Greenhill, Harvard/CfA; 28th October 2011

When and how did the first stars and galaxies form? We can say with certainty that the earliest generations existed during the first billion years after the Big Bang. However, detailed understanding is based largely on theory. Actual data are rare. In response, a new generation of radio telescopes is being built to observe the 21 cm transition of Hydrogen that traces the intergalactic medium from which the stars and galaxies formed. Many of the telescopes comprise massive arrays of VHF dipoles. Though these elements are electrically simple, the requisite signal processing is anything but, requiring supercomputers and development of new algorithms and techniques. Signs are good that GPU computing will be a critical enabling technology. I will describe the newly funded LEDA array and its goal of detecting in the Hydrogen line evidence of stars and galaxies when the Universe was < 1% of its present age.

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