Arguments

The source_catalog step uses the following user-settable arguments:

General parameters:

  • --suffix: A string value giving the file name suffix to use for the output catalog file. (Default=’cat’)

Aperture photometry parameters:

  • --aperture_ee1: An integer value of the smallest aperture encircled energy value. (Default=30)

  • --aperture_ee2: An integer value of the middle aperture encircled energy value. (Default=50)

  • --aperture_ee3: An integer value of the largest aperture encircled energy value. (Default=70)

  • --ci1_star_threshold: A floating-point value of the threshold compared to the concentration index calculated from aperture_ee1 and aperture_ee2 that is used to determine whether a source is a star. Sources must meet the criteria of both ci1_star_threshold and ci2_star_threshold to be considered a star. (Default=2.0)

  • --ci2_star_threshold: A floating-point value of the threshold compared to the concentration index calculated from aperture_ee2 and aperture_ee3 that is used to determine whether a source is a star. Sources must meet the criteria of both ci1_star_threshold and ci2_star_threshold to be considered a star. (Default=1.8)

General source finding parameters:

  • starfinder: A str indicating the source detection algorithm to use. Allowed values: 'iraf', 'dao', 'segmentation'. (Default= 'segmentation')

  • snr_threshold: A float value indicating SNR threshold above the background. Required for all star finders. (Default=3.0)

  • bkg_boxsize: A positive int indicating the background mesh box size in pixels. (Default=1000)

  • kernel_fwhm: A float value indicating the Gaussian kernel FWHM in pixels. (Default=2.0)

Additional source finding parameters for “segmentation”:

  • npixels: An int value indicating the minimum number of connected pixels that comprises a segment (Default=25)

  • connectivity: An int value indicating the connectivity defining the neighborhood of a pixel. Options are 4, i.e., connected pixels touch along edges, or 8, i.e, connected pixels touch along edges or corners (Default=8)

  • nlevels: An int value indicating the number of multi-thresholding levels for deblending (Default=32)

  • contrast: A float value indicating the fraction of total source flux an object must have to be deblended (Default=0.001)

  • multithresh_mode: A str indicating the multi-thresholding mode. Allowed values: 'exponential', 'linear', 'sinh'. (Default= 'exponential')

  • localbkg_width: An int value indicating the width of rectangular annulus used to compute local background around each source. If set to 0, then local background will not be subtracted. (Default=0)

  • apermask_method: A str indicating the method used to handle neighboring sources when performing aperture photometry. Allowed values: 'correct', 'mask', 'none'. (Default= 'correct')

  • kron_params: A tuple of float values indicating the parameters defining Kron aperture. If None, the parameters (2.5, 1.4, 0.0) are used. (Default=None)

  • deblend: A bool indicating whether to deblend sources. (Default=False)

Additional source finding parameters for “dao” and “iraf”:

  • minsep_fwhm: A float value indicating the minimum separation between detected objects in units of number of FWHMs. (Default=0.0)

  • sigma_radius: A float value indicating the truncation radius of the Gaussian kernel in units of number of FWHMs. (Default=1.5)

  • sharplo: A float value indicating The lower bound on sharpness for object detection. (Default=0.5)

  • sharphi: A float value indicating the upper bound on sharpness for object detection. (Default=2.0)

  • roundlo: A float value indicating the lower bound on roundness for object detection. (Default=0.0)

  • roundhi: A float value indicating the upper bound on roundness for object detection. (Default=0.2)

  • brightest: A positive int value indicating the number of brightest objects to keep. If None, keep all objects above the threshold. (Default=200)

  • peakmax: A float value used to filter out objects with pixel values >= peakmax. (Default=None)

Warning

Different source finding algorithms have different values for the sharplo, sharphi, roundlo and roundhi parameters. These parameters should be adjusted to match the algorithm selected by the starfinder parameter. See documentation for IRAFStarFinder and DAOStarFinder.