Michael P. Rupen [1]
November 18, 1997
Keywords: correlator, integration time, computing
The Millimeter Array will be large, agile, and sensitive enough to warrant integration times much less than a second. While on-the-fly total power mapping and variability studies both demand high time resolution, down to 10 microsec, neither requires vast data rates, as only very limited data need be written out. The real push comes from interferometric surveys, since the superb sensitivity implies that the area mapped will be limited by the shortest available integration period, rather than by thermal noise considerations. Dump times of 40 (8m/D)^2 milliseconds would allow most interesting sources to be mapped in reasonable times, although this depends greatly on the observing frequency, and less strongly on (reasonable values for) the sampling of the primary beam. Although these mosaics would result in huge amounts of data, for spectral line experiments well beyond current storage and processing techniques, it still seems worthwhile to aim for such rapid integrations, to allow continuum mapping immediately, and in hopes of clever software or impressive hardware advances over the several-decade lifetime of the instrument.
[1] NRAO
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