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