VLA CASA Pipeline-specline-CASA6.6.1

Spectral Line Pipeline Guide CASA 6.6.1

Pipeline Weblog

Pipeline Weblog (tar.gz)

S-band Continuum Pipeline Guide

In the S-band Continuum VLA Pipeline Guide we present a CASAguide for a VLA continuum dataset. As of late 2024, we modified the pipeline so that also spectral line data sets are properly calibrated (and imaged). This guide should be used in addition to the S-band Continuum VLA Pipeline Guide. We will only explain the additional steps that are performed for spectral line data sets.

The general description of the VLA pipeline, download, and known issues can be found on on the available at VLA Pipeline webpage.

Spectral Line data set identification and description

Spectral Line and Continuum data are not exactly separated as they both consist of several baseboards, split into spectral windows (spws), which contain many channels each. Typically, however, continuum data spans the entire frequency coverage of a receiver, has wide (MHz or similar) channel widths and is full polarization. Spectral Line datasets, on the other hand, have more narrow spectral windows with channels in the kHz range. There can be many spectral line windows, typically observed in parallel with continuum spws.

Spectral Line data set detection criteria

The spec line_spws parameter controls which spws will undergo continuum or spectral line processing.

ifv_importdata parameter specline_spws='auto'

The pipeline default is 'auto', other valid options are: 'none', 'all', or, for example, '2~3,6,7,9~12'. The 'auto' setting will process the windows more narrow that a standard continuum setup as being desired for spectral line science, 'none' will set all spectral windows to be processed as continuum, 'all' will process all spectral windows as spectral line, and the final example will process spectral windows 2, 3, 6, 7, 9, 10, 11, and 12 as spectral line windows.

Home Screen

Fig. O1: Overview.

The individual Stages

Stage 2. hifv_hanning: VLA Hanning Smoothing

maser_detection=False