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Sensitivity

The 1sigma point source sensitivity (in Jy) can be derived with:


\begin{displaymath}
\sigma = \frac{J_{\rm pK} T_{\rm sys}}{\eta \sqrt{N_a (N_a-1) T_{\rm ON} B}} \frac{1}{\sqrt{N_{\rm pol}}}
\end{displaymath} (1)

where

To provide the most realistic and up-to-date estimates of the sensitivity of NOEMA, NOEMA provides sophisticated sensitivity calculators via PMS (see Section [*]) and via the GILDAS software package ASTRO (please use the most recent GILDAS version when preparing your proposals). Both softwares use the same calculations, based on equation (1) given above, and are regularly updated with the latest NOEMA characteristics.

The point source sensitivity obviously depends on the observing frequency and hence a so called representative frequency has to be choosen in order to calculate the sensitivity in ASTRO and PMS. In PMS, the representative frequency has to be within the frequency range and for high spectral resolution projects within one of the high resolution spectral windows that are selected in the respective technical sheet. The representative frequency does not have to be identical to the actual tuning frequency. Please note, that due to the large bandwidth and the dual-sideband mode, the noise can vary significantly with frequency in the available frequency range. Especially, if one of the sidebands is close to a receiver band edge, significant differences in the noise can occur within and between the sidebands. This should be taken into consideration when setting the representative frequency for each tuning. Please note that PMS and ASTRO take into account variations of the noise across the entire 15.488 GHz bandwidth to calculate the continuum sensitivity. Both tools also account for the declination of the source to estimate the rms noise levels. Longer telescope times are needed for sources at low declinations ( $\delta < -10^\circ$) to achieve the same point-source sensitivity.


next up previous contents index
Next: Proposal Preparation Up: Capabilities Previous: The Wideband Correlator PolyFiX   Contents   Index
Gildas manager 2024-03-28