Pre facet calibration pipeline
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README.md

prefactor

The LOFAR pre-facet calibration pipeline.

Parsets for the genericpipeline that do the first calibration of LOFAR data. Originally in order to prepare said data for the Factor facet calibration (https://github.com/lofar-astron/factor), but also useful if you don't plan to run Factor.

It includes:

  • applying Ionospheric RM corrections
  • clock-TEC separation with transfer of clock from the calibrator to the target
  • some flagging and averaging of amplitude solutions
  • grouping of subbands by actual frequency
  • speed and disk usage improvements by optimized usage of NDPPP
  • (optional) wide-band cleaning in Initial-Subtract
  • diagnostic plots
  • at least some documentation on the wiki pages

The documentation can be found on the GitHub wiki pages: https://github.com/lofar-astron/prefactor/wiki

There are several pipeline parsets in this repository:

  • Pre-Facet-Calibrator.parset : The calibrator part of the "standard" pre-facet calibration pipeline.
  • Pre-Facet-Target.parset : The target part of the "standard" pre-facet calibration pipeline.
  • Initial-Subtract-Fast.parset : A pipeline that generates full FoV images and subtracts the sky-models from the visibilities. (Needed for facet-calibration.)
  • Initial-Subtract-IDG.parset : Same as Initial-Subtract.parset, but uses the image domain gridder (IDG) in WSClean
  • Initial-Subtract-IDG-LowMemory.parset : Same as Initial-Subtract.parset, but uses the image domain gridder (IDG) in WSClean for high-res imaging
  • Initial-Subtract-Deep.parset : Same as Initial-Subtract.parset, but it does only one image of the full bandwidth instead of imaging the bands separately.

Software requirements:

The Pre-Facet-Calibration pipeline and its scripts where developed by:

  • Alexander Drabent
  • Martin Hardcastle
  • George Heald
  • Andreas Horneffer
  • Soumyajit Mandal
  • David Rafferty
  • Carole Roskowinski
  • Jose Sabater Montes
  • Timothy Shimwell
  • Sarrvesh Sridhar
  • Reinout van Weeren
  • Wendy Williams

With special thanks to Stefan Froehlich for developing the genericpipeline.

The procedure is also mostly described in these papers:

  • van Weeren, R. J., Williams, W. L., Hardcastle, M. J., et al. 2016, ApJS, 223, 2
  • Williams, W. L., van Weeren, R. J., Röttgering, H. J. A., et al. 2016, MNRAS, 460, 2385