## Summary and interpretation

The point source sensitivity for an interferometric measurement reads

| (11)

where is the rms noise flux obtained by integration with an interferometer of identical antenna during the integration time in a frequency resolution with the system temperature, . is the conversion factor of any given interferometer antenna taking into account the typical amount of atmospheric decorrelation, , at the observed wavelength. The product is averaged over all independent baselines.

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.