Observing Band:


UV Weighting:



Estimated image rms noise -

*Proposers should request Elapsed Time which includes the necessary phase referencing scans (typically 30%).
L-band sensitivity estimates are based upon typical flagging strategies.
Estimates are based on high-elevation observing; lower elevations will give rise to higher noise.
Estimates for C-band assume a 5 GHz centre frequency. The sensitivity varies across the full 4.5 - 7.5 GHz range.
Estimate for K-band is preliminary. Actual observed result depend significantly on e.g. weather.
For more information visit http://www.e-merlin.ac.uk/observe.html.

The sensitivity of a single baseline between two antennas \(i,j\) can, according to Eq. 9-14 in Wrobel & Walker (1999), be written as $$ \Delta S_{ij} [\mathrm{Jy/beam}]= \frac{1}{\eta}\sqrt{\frac{SEFD_iSEFD_j}{2\Delta\nu\tau n_p}} $$ where \(SEFD_i\) is the System Equivalent Flux Density of antenna \(i\), \(\eta\) is the system efficiency (taken to be \(0.7\)), \(\Delta\nu\) the observing bandwidth [Hz], \(\tau\) the time on source [seconds], and \(n_p\) the number of polarisations averaged together [1 or 2]. Given \(n\) antennas where each baseline has equal weight (natural weighting), the standard deviation (sensitivity) of the combined image is the propagated standard error of the weighted mean: $$ \Delta S = \left(\sum_{i=1}^n \sum_{j=i+1}^n \Delta S_{ij}^{-2}\right)^{-1/2}=\frac{SEFD^*}{\eta\sqrt{2\Delta\nu\tau n_p}} \quad \mathrm{where}\\ SEFD^* = \left(\sum_{i=1}^n \sum_{j=i+1}^n \frac{1}{SEFD_iSEFD_j}\right)^{-1/2} $$ which sums over all baselines without double counting, i.e. \(n(n-1)/2\) terms.

Additional notes