The FFT telescope

by Andrew Lutomirski (MIT Physics)

Thursday 23 Apr 2009, 10:00 → 11:00 Europe/Stockholm

The 21 cm hyperfine transition in neutral will offer a wealth of new cosmological data about the early universe, but the signal, now redshifted to wavelengths of around two meters, is very weak. Building a large enough dish to detect and map the signal is all but impossible, and current attempts to map the 21 cm sky rely on aperture synthesis, in which a large number of small antennas are linked in software to produce images. This technique requires computing power that scales as the square of the number of computers, and for the huge arrays that we would like to build, the computation is impractical. By imagining the electric field on the ground as the Fourier transform of the signal from the sky, we believe that we can dramatically reduce the computing power we need and eventually build radio arrays that dwarf those possible with traditional aperture synthesis.

Slides 90423_fftt.pdf