User Parameters - Continuum Source-finding

Source-finding is run in two ways within these scripts. It can be run after each individual beam is imaged, and then again after the mosaicking has completed.

Only continuum source-finding is done at this point - spectral-line source-finding will be added in the future.

The source-finding applies a spatially-varying signal-to-noise threshold, and fits 2D Gaussians to detected islands to create a component catalogue.

At this point, only a limited set of Selavy’s possible parameters are made available through these scripts. This will likely increase, but in the interim you can edit the sbatch files that are created and re-run it yourself.

Variable	Default	Parset equivalent	Description
DO_SOURCE_FINDING	false	none	Whether to do the source-finding with Selavy on the individual beam images and the final mosaic.
SELAVY_NSUBX	6	nsubx (Selavy Basics)	Number of divisions in the x-direction that divide the image up, allowing parallel processing in the source-detection.
SELAVY_NSUBY	3	nsuby (Selavy Basics)	Number of divisions in the y-direction that divide the image up, allowing parallel processing in the source-detection.
SELAVY_SNR_CUT	5.0	snrcut (Selavy Basics)	The signal-to-noise ratio threshold to use in the source-detection.
SELAVY_FLAG_GROWTH	true	flagGrowth (Selavy Basics)	A flag indicating whether to grow detections down to a lower threshold.
SELAVY_GROWTH_CUT	3.0	growthCut (Selavy Basics)	The secondary signal-to-noise threshold to which detections should be grown.
SELAVY_VARIABLE_THRESHOLD	true	VariableThreshold (Thresholds in Selavy)	A flag indicating whether to determine the signal-to-noise threshold on a pixel-by-pixel basis based on local statistics (that is, the statistics within a relatively small box centred on the pixel in question).
SELAVY_BOX_SIZE	50	VariableThreshold.boxSize (Thresholds in Selavy)	The half-width of the sliding box used to determine the local statistics.