NOISE operation

The NOISE operation adds noise to the model visibilities. The noise values are drawn for each baseline from a Gaussian distribution, the width of which is given by the appropriate system equivalent flux density (SEFD) in each frequency channel. The values for the SEFD were derived from van Haarlem et al. (2013) 1. For the LOFAR2.0 LBA stations, the SEFD is estimated using 0.71 times the mean of the SEFD of the modes LBA_INNER and LBA_OUTER.

Note

If this operation is used in conjunction with the PREDICT operation, then it should always be done after PREDICT so that the data to which noise are added are not overwritten by the prediction.

Note

For a realistic simulation, you should apply the bandpass (using the mode='ms') AFTER applying the noise.

Parameters

The following parameters are available for this operation:

outputColumn

This parameter is a string (default is 'DATA') that sets the column name to which noise is added

factor

This parameter is a scalar that can be used to tweak the noise scale. The default is 1.0.

1

van Haarlem M. P., et al. 2013, A&A, 556, 2