The rms brightness temperature is related to the point source sensitivity by
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(2) |
For a typical experiment with configuration BC or CD, tracking the source for 8 hours (but spending 2 hours on calibration) on each
configuration, we obtain =0.11 K and
=0.03 K, for 0.625 MHz channel spacing with the spectral
correlator, with the same assumptions as above at 90 GHz. The factor
is increased by uniform weighting and tapering: the amount
depends on the uv-coverage and on the phase noise as a function of baseline lengths, but tapering also increases the synthesized
beam size.
An equivalent way to look at noise in a map is by comparison to the single-dish sensitivity (given here for position switching)
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(3) |
The mapping sensitivity is roughly related to by
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(4) |