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Noise vs signal

One subtlety is that the noise is unaffected by the atmospheric decorrelation, in contrast with the signal, because noise is a random process as the turbulence phase noise.

But the conversion factor, \ensuremath{J_\ensuremath{\mathrm{ant}}^\ensuremath{\mathrm{int}}}, is applied to the data that can contain signal as well as noise. Any attempt to measure the noise rms on visibilities or imaged data will thus results in a standard deviation larger than the one given in Eq. 6 by a factor \ensuremath{\eta_\ensuremath{\mathrm{atm}}}. So when we estimate the noise level of an interferometer, we need to take into account the interferometric conversion factor that depends on the typical weather conditions (i.e., the atmospheric rms phase noise). This gives

\begin{displaymath}
\ensuremath{\sigma_\ensuremath{\mathrm{Jy}}} = \frac{\ensur...
...emath{d\nu}\,\ensuremath{\Delta t_\ensuremath{\mathrm{}}}}}.
\end{displaymath} (9)



Gildas manager 2023-06-01