Step 4 Overview & Scripts

In this step, we finally work with the line data to prepare them for imaging. We apply all phase alignment and self-calibration solutions generated from the continuum, and perform continuum subtraction.

Scripts for Step 4 - Prepare the lines:

• step4_prepare_lines.py # main script

• step4_detour.py # for phase alignment

• dictionary_data.py # loads data_dict

• step1_utils.py # loads multiple functions

• analysisUtils (analysis_scripts/) # for channel strings

(Manual Flagging: Like for the continuum, we do no manual flagging.)

Averaging Down the Continuum: Having gained what we need from the continuum self-calibration, we return to the pipeline calibrated visibilities (uid*.ms.split.cal.source measurement sets) and spectrally average down the continuum.

Apply Phase Shifts: On a per-EB basis, we apply the same phase center realignments that we generated with the continuum data.

Apply Self-Calibration Solutions: On a per-EB basis, we apply the same calibration gain tables that we generated with the continuum data.

Continuum Subtraction: We perform continuum subtraction in the uv-plane using the uvcontsub task.

Create Final Line Measurement Sets: Finally, we combine the corresponding SPWs across execution blocks and obtain final measurement sets ready for imaging.