Fast Fourier transform telescope
Name
Tegmark-2009-Fast Fourier transfo.pdf
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Author(s)
Tegmark, Max Erik
Zaldarriaga, Matias, 1971-
Date Issued
April 2009
Journal
Physical Review D
Publisher
American Physical Society
Citation
Tegmark, Max , and Matias Zaldarriaga. “Fast Fourier transform telescope.” Physical Review D 79.8 (2009): 083530. (C) 2010 The American Physical Society.
Version
Final published version
Abstract
We propose an all-digital telescope for 21 cm tomography, which combines key advantages of both
single dishes and interferometers. The electric field is digitized by antennas on a rectangular grid, after
which a series of fast Fourier transforms recovers simultaneous multifrequency images of up to half the
sky. Thanks to Moore’s law, the bandwidth up to which this is feasible has now reached about 1 GHz, and
will likely continue doubling every couple of years. The main advantages over a single dish telescope are
cost and orders of magnitude larger field-of-view, translating into dramatically better sensitivity for largearea
surveys. The key advantages over traditional interferometers are cost (the correlator computational
cost for an N-element array scales as Nlog[subscript 2]N rather than N[superscript 2]) and a compact synthesized beam. We argue
that 21 cm tomography could be an ideal first application of a very large fast Fourier transform telescope,
which would provide both massive sensitivity improvements per dollar and mitigate the off-beam point
source foreground problem with its clean beam. Another potentially interesting application is cosmic
microwave background polarization.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
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DOI of Published Version
http://dx.doi.org/10.1103/PhysRevD.79.083530
