3C277.1 e-MERLIN Workshop

This e-MERLIN continuum tutorial is split into two parts which should be done in order. The tutorial covers a lot of what is covered in the EVN tutorial but also covers extra techniques such as advanced decovolution algorithms and baseline-based calibration.

3C277.1 is a twin-lobed radio galaxy. These C-band (4-7.3 GHz) e-MERLIN observations were made specifically for this tutorial but previous MERLIN and VLA images have been published by Ludke et al. 1998 and Cotton et al. 2006. The data have already been converted from fitsidi to a Measurement Set (MS), and preparatory steps such as correcting the $uv$ coordinates and averaging have been performed.


Data download instructions

To download these data use the following link. If you want to skip to part 2 and just do the imaging then use the other link i.e. 3C277.1 data (pt2 only).

The following scripts are contained in these files, and the files can be untarred using tar -xzvf. The part 1 and 2 bundle (3C277.1 data (1.3GB) / 3c277_workshop.tar.gz) contains:

  • all_avg.ms - measurement set after some pre-processing
  • 3C277.1_cal_outline.py - calibration script equivalent of the guide for part 1
  • 3C277.1_cal_all.py.tar.gz - compressed script for part 1 in case you get stuck
  • 3C286_C.clean.model.tt0 - Amplitude calibrator model
  • all_avg.flags.txt - list of flags
  • 3C277.1_imaging_outline.py - calibration script equivalent of the guide for part 2
  • 3C277.1_imaging_all.py.tar.gz - compressed script for part 2 in case you get stuck

While the part 2 only bundle (3C277.1 data (pt2 only) (464MB) / 3c277_workshop_pt2_only.tar.gz) contains:

  • 3C277.1_imaging_outline.py - calibration script equivalent of the guide for part 2
  • 3C277.1_imaging_all.py.tar.gz - compressed script for part 2 in case you get stuck
  • 1252+5634.ms.tar.gz - semi-calibrated measurement set if starting at part 2

As stated before, there are two parts: calibration and imaging. Follow the links below to complete the tutorials. If you would like to skip a step of the tutorial, there are instructions on the webpages below on how to move your dataset up to the required calibration step for the tutorial.

Anyways, if you have the correct data then move onto part 1 or part 2 (or ERIS tutorial) using the links below:


Credits

This workshop is based upon the original tutorial developed by Anita Richards (Uni. of Manchester) and the subsequent updating by Javier Moldon (Uni. of Manchester). The most recent update by Jack Radcliffe (Uni. of Manchester/ Uni. of Pretoria) has updated this to the newest CASA versions. If you find bugs or problems please contact Jack Radcliffe using the form below please!