Data Product Definitions
The Continuum Imaging Pipeline (CIMG) produces a number of data products as outputs depending on the imaging mode requested in the configuration file. The intended Observatory Data Product (ODP) definitions are captured in the following Solution Intent page on Confluence, and the current outputs in the sections below.
The pipeline configuration file
has a number of parameters that control the data products generated. For example, the target folder
for the data products is determined by the --output-dir CLI parameter. The
image_settings.name parameter in the configuration file determines the prefix for the data (by
default "cimg_odp").
Image Data Products
The main data products generated by the pipeline are summarised in the table below. For each frequency channel imaged, as well as for the full observation combined across all channels (MFS), the following FITS files are produced:
File Name (per channel) |
File Name (combined channels) |
Description |
|---|---|---|
|
|
Dirty image |
|
|
Clean image |
|
|
Clean image with primary beam correction applied |
|
|
Model image (flat noise) |
|
|
Model image with primary beam correction applied |
|
NA |
Model images for facet based prediction |
|
|
Residual of beam corrected clean image and model image |
|
|
Residual of flat noise image and model |
|
NA |
Represents the Stokes I response: a combination of the average beam and average gain solution corrections. |
In the above 00xx represents the filename for each frequency channel. For example, for a run
requesting 12 frequency channels there will be 12 such files, numbered from 0000 through
0011.
Direction-dependent PSF Files
In addition to the files above, for each frequency channel, wsclean calculates direction dependent PSFs on an 8 by 8 grid across the image (the number of grid tiles may be made configurable in a future release). More detail concerning this is available from the wsclean documentation. For a run using 12 frequency channels, for example, these PSF files are available as:
cimg_odp-d0000-0000-psf.fits…
cimg_odp-d0000-0011-psf.fits…
cimg_odp-d0063-0000-psf.fits…
cimg_odp-d0063-0011-psf.fits
where d0000 to d0063 represent the 64 tiles in the 8 by 8 grid, and 0000 to 0012
represent the frequency channels.
CLEAN component lists
As part of the imaging process, wsclean produces a source catalog in makesourcedb
format containing a detailed component list of the sources used in the model of the final image. The
catalog is available as: cimg_odp_sources.txt. In addition, the cimg_odp_sources-pb.txt file
contains the primary beam corrected source components. Further details can be found in the wsclean
component list documentation.