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jradcliffe5 edited this page Jul 4, 2022 · 19 revisions

Introduction

Welcome to the VPIPE wiki! This wiki outlines how to use the VLBI pipeline built by Jack Radcliffe. If you have any issues with the code feel free to create and issue or generate a pull request. This pipeline was built mostly by me so mistakes are probably there!

The wiki is designed to explain and guide the user through the steps conducted by the pipeline. Each step has a page to itself and you can use this page to get to these. This will give you help in completing the parameter file. This home page provides an overview of the pipeline and includes some future directions. Currently (as of 04-07-2022), the pipeline has been tested on continuum data sets from the European VLBI Network (EVN), Very Long Baseline Array (VLBA) and the Long Baseline Array (LBA), however, it can easily be adapted for other arrays.

The pipeline was built to accommodate the many large VLBI data sets on the horizon along with promoting and transitioning VLBI data processing from AIPS to CASA. This pipeline includes some wide-field VLBI specialist codes such as primary beam correction, the casting of calibration solutions to multiple phase centres and multi-source self-calibration.

Pipeline steps

This section outlines the steps in order of execution and you can visit each of these pages on how to input the correct parameters. However, before doing this, I recommend learning how to execute the pipeline and what input files are required for execution.

Preparing and executing the pipeline

Now that you know the ropes, follow the sections to calibrate your VLBI data and set the appropriate parameters. For the first time, it is recommended to run each step individiually.

Standard VLBI steps

  1. Preparing fitsidi data - EVN/LBA only (prepare_data)
  2. Import fitsidi data to CASA measurement set(import_fitsidi)
  3. (make_mms)
  4. (apriori_cal)
  5. (init_flag)
  6. (fit_autocorrs)
  7. (sub_band_delay)
  8. (bandpass_cal)
  9. (phase_referencing)
  10. (apply_target)

Wide-field steps

  1. (apply_to_all)
  2. (mssc)
  3. Preparing EVN data
  4. Import fitsidi
  5. make mms
  6. apriori calibration
  7. initial flagging
  8. fit autocorrelations
  9. sub band delay
  10. bandpass calibration
  11. phase_referencing
  12. apply target(s)
  13. primary_beam_correction

Additional Scripts

The pipeline also comes with some additional scripts that can help you obtain better results from the pipeline. Please follow the links for information on the codes:

  • copy_ms_pols.py - copies one polarisation to the other, useful as CASA cannot deal with single pols
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