Keywords: astro-noema-sensitivity-estimator

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## Signal decorrelation

characterizes the antenna hardware, i.e. it assumes perfect atmospheric conditions or the use of autocorrelations, as in single-dish measurements. In interferometric mode, the phase of the turbulent atmosphere above each antenna of a given baseline has a random part that causes an additional ``attenuation'' of the amplitude of the correlation. A point source of 1Jy flux will appear as a source of Jy flux if we only use the factor. This is called atmospheric decorrelation and it depends on the weather during the observations.

However, the last calibration step of interferometric data is to measure a point source of known flux to deduce the actual conversion factor, , taking into account the atmospheric decorrelation that happens during the observations. By definition of , we yield

| (7)

It can be shown that is related to the atmospheric rms phase noise ( ) through

| (8)

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