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Starting from the point source sensitivity

As a summary, the point source sensitivity for an interferometric measurement reads

\begin{displaymath}
\ensuremath{\sigma_\ensuremath{\mathrm{Jy}}} = \frac{\ensur...
...emath{d\nu}\,\ensuremath{\Delta t_\ensuremath{\mathrm{}}}}},
\end{displaymath} (10)

where \ensuremath{\sigma_\ensuremath{\mathrm{Jy}}} is the rms noise flux obtained by integration with an interferometer of \ensuremath{n_\ensuremath{\mathrm{ant}}} identical antenna during the \ensuremath{\Delta t_\ensuremath{\mathrm{}}} integration time in a frequency resolution \ensuremath{d\nu} with a system temperature given by \ensuremath{T_\ensuremath{\mathrm{sys}}}. \ensuremath{J_\ensuremath{\mathrm{ant}}^\ensuremath{\mathrm{int}}} is the conversion factor of a typical interferometer antenna taking into account the typical amount of atmospheric decorrelation at the observed wavelength.

Equation 10 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.


next up previous contents
Next: We yield the interferometric Up: The interferometric extended source Previous: The interferometric extended source   Contents
Gildas manager 2023-06-01