6.6.4 APEX QA Modules: (Mosaic) Point Source Image
Command Line Equivalent: create_residual_images (for apex.pl) or create_residual_mosaic (for apex_1frame.pl).
Default Output Directory: <output_dir>
Depends on: Output of APEX (User List) Multiframe or APEX (User List) Single Frame
Important Notes: The name of this module is “Point Source Image” in the APEX QA Multiframe pipeline, and “Mosaic Point Source Image” in the APEX QA Single Frame Pipeline. The functionality is the same.
PURPOSE
This module is used to subtract the sources from the input images or the input mosaic to create a residual image(s). This is extremely useful for testing how well the PRF fitting in APEX is working.
INPUT
PRF Resample X(Y) Factor: (int) This is the same PRF Resample X(Y) Factor as used in the Source Estimate module. It is the ratio of the input image pixel size to the PRF pixel size in the x- and y-direction.
PS Image X(Y) size: (int, odd) If present and smaller than the PRF array size, the PRF array will be cut to this size. The units are data pixels.
Flux Column Name: (char) The name of the column in the Extract Table that corresponds to the flux of each point source.
Input RA Dec: The units of the positional input data. Choices are “Pixel Coordinates” and “RA & Dec”.
X(Y) Column Name: (char) The name of the X and Y positional columns to be read from the Extract Table. Options are 'RA’ and 'Dec' or 'x' and 'y'. If 'x' and 'y' are used, the Fiducial Image Frame table must also be specified in the Initial Setup.
Normalization Radius: (int) This is the same parameter as used in the Source Estimate module. The PRF flux is normalized within this radius (in PRF pixels). By default, the PRF is normalized to the whole PRF array.
Outer Radius: (int) Cuts a circular PRF image of this size in pixels. By default, the whole image is used.
Hole Radius: (int) Cuts a hole in the PRF image of this size in pixels.
Residual output subdirectory: The name of the output subdirectory for the point source subtracted image(s). The default is Residual-ApexQA.
COMMAND LINE INPUT
When running in Multiframe mode (i.e. on the output of apex.pl):
&POINTSOURCEIMAGE
PRF_ResampleX_Factor = 100,
PRF_ResampleY_Factor = 100,
Input_RA_Dec = 1,
X_Column_Name = 'RA',
Y_Column_Name = 'Dec',
Normalization_Radius = 1000,
Outer_Radius = 44,
Hole_Radius = 21,
&END
When running in Single Frame mode (i.e. on the output of apex_1frame.pl) the parameters are identical but the module block starts with the keyword:
&MOSAIC_POINTSOURCEIMAGE
OUTPUT
The residual images are written to the specified output directory and are called residual*.fits
DISCUSSION
This module is used to subtract the sources from the input images or the input mosaic to create a residual mosaic. This is extremely useful for testing how well the PRF fitting is working. The two modes (Single Frame and Multiframe) use different keywords for triggering the module to run, and for specifying the parameter block. Parameters PRF Resample X(Y) Factor and Normalization Radius are the same parameters as used in the Source Estimate module, and should be set to the same values as previously used.
