As a summary, the point source sensitivity for an interferometric measurement reads
where
Equation
is true only when the source is unresolved,
i.e., there is no effect of beam dilution. In practice this is rarely the
case because the interferometer tries to resolve the source. Thus, this
noise formula should be used with caution when preparing the
observations. In practice, this formula is useful when one wishes to
compare the sensitivity of two different interferometer. Indeed, this point
source sensitivity is independent of the interferometer synthesized beam
that depends on the details of the observations and, in particular, the
interferometer configuration and the completeness of the Earth synthesis.