Uvcontsub

Help on uvcontsub task:

Continuum fitting and subtraction in the uv plane

        
        A polynomial of the desired order is fit to each baseline/time across the
        specified channels that define the continuum emission.  The data may
        be averaged in time to increase the signal to noise.  This fit
        represents a uv-data model of the continuum across all channels.
        
        For fitmode='subtract', the fitted continuum uv spectrum is
        subtracted from all channels and the result (presumably only
        line emission) is stored in the CORRECTED_DATA.  The
        continuum fit is stored in the MODEL_DATA.

        For fitmode='model' the continuum model is stored in the
        MODEL_DATA; but the CORRECTED_DATA is unaffected.

        For fitmode='replace' the continuum model is stored in
        the CORRECTED_DATA; this is useful to image the continuum model
        result.  You will have to rerun applycal to place the calibrated
        data back in the CORRECTED_DATA

        Keyword arguments:
        vis -- Name of input visibility file
                default: none; example: vis='ngc5921.ms'
        field -- Field selection
                default: field = '' means select all fields
                field = 1 # will get field_id=1 (if you give it an 
                        integer, it will retrieve the source with that index.
                field = '1328+307'  specifies source '1328+307'
                field = '13*' will retrieve '1328+307' and any other fields
                   beginning with '13'
        fitspw -- Selection of spectral windows and channels to use in the
                  fit for the continuum, using general spw syntax
                default: ''=all; example: fitspw='0:5~30;40~55'
        spw -- Optional per spectral window selection of channels from
               which to subtract the continuum. 
                default: spw='', means subtract from all channels for
                  each spw that had a continuum estimated
               Also, this specifies which spw/chan will be split
               out if splitdata=True.
        solint -- Timescale for per-baseline fit (units optional)
                default: 'int' --> no averaging, fit every integration;
                example: solint='10s'  --> average to 10s before fitting
                         10 or '10' --> '10s' (unitless: assumes seconds)
                options: 'int' --> per integration

        Keyword arguments:
        vis -- Name of input visibility file
                default: none; example: vis='ngc5921.ms'
        field -- Field selection
                default: field = '' means select all fields
                field = 1 # will get field_id=1 (if you give it an 
                        integer, it will retrieve the source with that index.
                field = '1328+307'  specifies source '1328+307'
                field = '13*' will retrieve '1328+307' and any other fields
                   beginning with '13'
        fitspw -- Selection of spectral windows and channels to use in the
                  fit for the continuum, using general spw syntax
                default: ''=all; example: fitspw='0:5~30;40~55'
        spw -- Optional per spectral window selection of channels from
               which to subtract the continuum. 
                default: spw='', means subtract from all channels for
                  each spw that had a continuum estimated
               Also, this specifies which spw/chan will be split
               out if splitdata=True.
        solint -- Timescale for per-baseline fit (units optional)
                default: 'int' --> no averaging, fit every integration;
                example: solint='10s'  --> average to 10s before fitting
                         10 or '10' --> '10s' (unitless: assumes seconds)
                options: 'int' --> per integration
                         'inf' --> per scan
        fitorder -- Polynomial order for the fit of the continuum
                default: 0 (constant); example: fitorder=1
        fitmode -- Use of the continuum fit model
                default: 'subtract'; example: fitmode='replace'
                Options: 
                'subtract'-store fitted continuum model in MODEL and
                   subtract this continuum from data in CORRECTED to
                   produce line-emission in CORRECTED.
                'model'-store fit continuum model in MODEL, but
                   do not change data in CORRECTED.
                'replace'-replace CORRECTED with continuum mode fit.
        splitdata -- Split out continuum and continuum subtracted line data
                default: 'False'; example: splitdata=True
                The derived continuum data will be placed in: vis.cont
                The continuum subtracted data will be placed in: vis.contsub
                The spw/channels selected are given in spw
        async -- Run task in a separate process (return CASA prompt)
                default: False; example: async=True