• SCUBA2_DISPLAY_PCA

SCUBA2_DISPLAY_PCA

Description

A simple PICARD recipe to apply Principal Components Analysis processing to raw SCUBA-2 data and display the results graphically.

The list of input data files should contain a fast-ramp flatfield (taken prior to the target data). There is no limit on the number of files that can be given, but note that processing is delayed to the last file in the list and all of the input files are passed to SMURF:SC2CLEAN. Be aware that this could take some time.

The results for each chosen PCA component are displayed in up to two KAPVIEW windows. The left-hand column displays the amplitude scaled between +/-2 sigma, the next column displays the component as a function of time and the third column shows the power spectrum of each component. Each KAPVIEW window can display results for up to 4 PCA components.

It is possible to use this recipe purely as a display for existing results, allowing different ranges of PCA components to be examined. The recipe leaves the PCA products on disk for reuse. However, see the parameters PCA_REUSE and PCA_KEEPFILES below for how to delete all files created by this recipe.

Notes

Input data should be from a single subarray only, and for a single observation. Processing will terminate with an error if this is not the case.

This recipe runs on raw SCUBA-2 data.

Since this recipe requires at least 2 data files it is recommended that the filenames be placed in a file (called, say, data.lis) and that file used on the command line call to PICARD, i.e.,

% picard -log s SCUBA2_DISPLAY_PCA `cat data.lis`

Available recipe parameters

The following parameters can be set via the -recpars option:

• KEEPFILES
  • Flag to indicate which files should be kept on disk. Default is 1 which keeps the PCA amplitude, component and power spectrum files on disk. A value of 0 deletes all files, while a value of -1 indicates that all files should be kept on disk.
• PCA_COMP
  • PCA components to analyze and display. Default is 0 to 5. The components may be specified either as a comma-separated list (e.g. 0,1,2,3 etc - they need not be contiguous or in order), or as a Perl array slice (e.g. 0..3). The number of components must be no more than 8. If more than 8 are given, only the first 8 are used.
• PCA_REUSE
  • Flag to indicate that existing data should be used if present. Default is 1 (reuse).