Output

Catalog

SourceXtractor++ writes out a catalog file with a filename set by the --output-catalog-filename option. Note that if no output-catalog-filename is set in the command line nor in the configuration file, then the catalog is printed in ASCII to the standard output.

The --output-catalog-format option sets the format of the output catalog. Currently available options are FITS for a FITS binary table, and ASCII for an ASCII table.

Output properties

SourceXtractor++ computes only what is required to produce the output catalog and diagnostics. While the original SExtractor would automatically trigger the measurement processes depending on the columns the user would like to be included in the catalog, SourceXtractor++ adopts a more coarse-grained and modular approach through the concept of properties.

Properties regroup several scalar or vector values obtained in the context of a specific image measurement or processing. Properties are requested by giving as argument to the --output-properties a coma-separated list of keywords. For example, requesting the PixelCentroid property (the default) adds both the pixel_centroid_x and pixel_centroid_y columns to the output catalog. Note that additional, custom columns may be inserted in the catalog through calls to add_output_column in the measurement script.

The --list-output-properties option prints out the complete list of available properties known to SourceXtractor++. The lists of catalog columns for the requested properties and for all properties are displayed using --property-column-mapping and --property-column-mapping--all options, respectively.

The complete list of columns and properties currently known to SourceXtractor++ is given below.

Diagnostic files

Additional files can be generated by SourceXtractor++, providing diagnostics about the source extraction and measurement processes. Currently only check-images, which are FITS images containing maps of various types, are produced. Each of the following options, followed by a filename, may be set to trigger the production of a check-image:

  • check-image-model-fitting: noiseless image of the best-fitting source models

  • check-image-residual: model-fitting residuals

  • check-image-background: bicubic-spline-interpolated background model

  • check-image-variance: variance map

  • check-image-segmentation: map of detected objects after the segmentation stage

  • check-image-partition: map of detected objects after the partition stage

  • check-image-grouping: map of detected objects after the grouping stage

  • check-image-filtered: filtered copy of the detection image

  • check-image-thresholded: filtered, thresholded copy of the detection image

  • check-image-auto-aperture: map of automatic photometric apertures

  • check-image aperture: map of disk aperturess

  • check-image-moffat: noiseless image of the best-fitting extended Moffat models

  • check-image-psf: PSF map