hifa_targetflag

hifa_targetflag(vis=None, parallel=None) → ResultsList[Results]

Flag target source outliers.

This task flags obvious outliers in the target source data. The calibration tables and flags accumulated in the cal library up to this point are pre-applied, then hif_correctedampflag is called for just the TARGET intent. Any resulting flags are applied and the calibration library is restored to the state before calling this task.

Because science targets are generally not point sources, the flagging algorithm needs to be more clever than for point source calibrators. The algorithm identifies outliers by examining statistics within successive overlapping radial uv bins, allowing it to adapt to an arbitrary uv structure. Outliers must appear to be a potential outlier in two bins in order to be declared an outlier. To further avoid overflagging of good data, only the highest threshold levels are used (+12/-13 sigma). This stage does can add significant processing time, particularly in making the plots. So to save time, the amp vs. time plots are created only if flags are generated, and the amp vs. uv distance plots are made for only those spws that generated flags. Also, to avoid confusion in mosaics and single field surveys, the amp vs. uv distance plots only show field IDs with new flags.

Example of flagging high outliers in the calibrated science target visibility amplitudes.

Parameters:

• vis --

  The list of input MeasurementSets. Defaults to the list of MeasurementSets specified in the hifa_importdata task. '': use all MeasurementSets in the context

  Examples: 'ngc5921.ms', ['ngc5921a.ms', ngc5921b.ms', 'ngc5921c.ms']

• parallel --

  Process multiple MeasurementSets in parallel using the casampi parallelization framework.

  Options: 'automatic', 'true', 'false', True, False

  Default: None (equivalent to False)

Notes

QA = 1 - (fraction of data newly flagged).

Returns:

The results object for the pipeline task is returned.

Examples

1. Run with recommended settings to flag outliers in science target(s):

>>> hifa_targetflag()