CREATE_MOMENTS_MAP

Creates a moments map from a spectral-line cube

Description:

This recipe is used to create a moments map (or multiple moments maps) from a cube. It smooths the cube in frequency and spatial extents, then finds 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.

Notes:

The Clumpfind algorithm selects the emission by walking down peaks to lower intensities.

Available Parameters :

The following parameters can be set via the -recpars option:
BASELINE_ORDER
The polynomial order that will be used when estimating baselines. [1]
FREQUENCY_SMOOTH
The number of channels to smooth in the frequency axis when smoothing to determine baselines. This number should be small ( ∼10) for narrow-line observations and large ( ∼25) for broad-line observations. [25]
MOMENTS
The moment maps to create. These are any of the values allowed for the ESTIMATOR parameter to the COLLAPSE task, but in reality this should probably be ’ integ’ , ’ iwc’ , and/or ’ itd’ . Any number of moments can be given in a comma-separated string. [’ integ’ ]
MOMENTS_LOWER_VELOCITY
An optional lower velocity in km/s, below which no data will be used when creating the moments map. When it is undefined, the full velocity range is used. [undef]
MOMENTS_SNR
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]
MOMENTS_UPPER_VELOCITY
An optional upper velocity in km/s, above which no data will be used when creating the moments map. When it is undefined, the full velocity range is used. [undef]
SPATIAL_SMOOTH
The number of pixels to smooth in both spatial axes when smoothing to determine baselines. [3]

Output Data

For each moment chosen through the MOMENTS parameter there is NDF called pg <utdate >_ <obsno >_ <moment >, where <utdate > is the UT date, <obsno > is the observation number (without any leading zeroes), and <moment > is the moment name. A spectrum from the highest signal in NDF pg <utdate >_ <obsno >_sp.
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