Appendix A
PICARD

There are two Picard recipes which can be used with ACSIS data and are of general interest:

A.1 CREATE_MOMENTS_MAP

This recipe is used to create a moments maps from a cube. It smooths the cube in frequency and spatial extents, then uses the ClumpFind algorithm to find clumps of emission. Everything in the cube not found in a clump is masked out, then the masked cube is collapsed to form the moments map.

Recipe options:

• BASELINE_ORDER: The polynomial order for baseline fitting [1]
• CLUMP_METHOD: Method to find emission in the data (clumpfind/fellwalker/thresh) [clumpfind]
• FREQUENCY_SMOOTH: Smoothing kernel size in channels along the frequency axis for baseline determination [25]
• MOMENTS: Which moments maps to create (integ/iwc/itd) [integ]
• MOMENTS_LOWER_VELOCITY: An optional lower velocity in km s$-1$, below which no data will be used when creating the moments map [undef]
• MOMENTS_UPPER_VELOCITY: An optional upper velocity in km s$-1$, above which no data will be used when creating the moments map [undef]
• MOMENTS_SNR: Selects whether or not to do clump detection on an signal-to-noise cube instead of the signal cube. Enabling this is useful for data taken in varying conditions. [0]
• SPATIAL_SMOOTH: Smoothing kernel size in pixels along both spatial axes for baseline determination [3]

A.2 MOSAIC_JCMT_IMAGES

This recipe co-add the given files into a single map while correctly handling the exposure time FITS header and other NDF components. The maps are combined using inverse-variance weighting and the output variance is derived from the input variances. You can choose either wcsmosaic or a combination of wcsalign and the Ccdpack application makemos to mosaic the images.

Recipe options:

• MOSAIC_EACH: Flag to indicate whether the data should be mosaicked by individual object or combined into a single output file.
• MOSAIC_TASK: Name of mosaicking task to use, wcsmosaic or makemos. [wcsmosaic]
• MAKEMOS_METHOD: Image combination method for makemos, may be median (default), mean or sigmas. See ccdpack manual for advice on choosing a method.
• MAKEMOS_SIGMAS: Sigma-clipping threshold if MAKEMOS_METHOD = sigmas. [4]
• MASK_LOWVAR: Flag to indicate that pixels with anomalously-low variances should be removed before mosaicking. [0]
• WCSMOSAIC_METHOD: wcsmosaic and wcsalign pixel-spreading method. [nearest]
• WCSMOSAIC_PARAMS: additional parameters that may be specified with wcsmosaic.

A.3 Running PICARD recipes

There are a number of options available when running Picard recipes. The example below illustrates most of them.

• The recipe parameters are listed in a file called params.ini. It is called by the recpars option. This file has the same .ini format used by the Orac-dr pipeline (see Section 6.2).
• The recipe name need to be in uppercase.
• If you need to supply multiple files you can do so by listing them in a file (myfilelist.lis in this example).
• Like the Orac-dr pipeline, the -log option specifies whether the log file should be written to the screen [s], a file [f] or an xwindow [x].