Difference between revisions of "Setjy"

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(Created page with '<pre> Fills the model column with the visibility of a calibrator The task places the model visibility amp and phase associated with a specified source (generally a…')
 
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{{setjy}}
Fills the model column with the visibility of a calibrator
 
 
 
      The task places the model visibility amp and phase associated
 
      with a specified source (generally a calibrator).
 
      The simplest way to to enter the flux density
 
      (I,Q,U,V) explicitly, but this is valid only for a point source.
 
 
 
      For an extended source, the clean model (image.model) can be
 
      specified and the model visibilities associated with this clean
 
      model is placed in the visibility model column.
 
 
 
      Models are available for 3C48, 3C138, 3C286 between
 
      1.4 and 43 GHz.  3C147 is available above 13 GHz.  These models
 
      are scaled to the precise frequency of the data.  Only I source
 
      model can be inserted at a time.
 
 
 
      The location of the models are system dependent:  At the AOC and CV,
 
      the models are in the directory::/usr/lib/casapy/data/nrao/VLA/CalModels
 
      or /usr/lib64/casapy/data/nrao/VLA/CalModel.
 
 
 
      Setjy need only be run on the calibrator sources with a know flux
 
      density and/or model.
 
 
 
      Keyword arguments:
 
      vis -- Name of input visibility file
 
              default: none.  example: vis='ngc5921.ms'
 
      field -- Select field using field id(s) or field name(s).
 
              default: ''=all fields, but run setjy one field at a time.
 
                [run listobs to obtain the list id's or names of calibrators]
 
              If field string is a non-negative integer, it is assumed a field index
 
                otherwise, it is assumed a field name
 
              field='0~2'; field ids 0,1,2
 
              field='0,4,5~7'; field ids 0,4,5,6,7
 
              field='3C286,3C295'; field named 3C286 adn 3C295
 
              field = '3,4C*'; field id 3, all names starting with 4C
 
      spw -- Select spectral window/channels
 
              default: ''=all spectral windows and channels
 
              spw='0~2,4'; spectral windows 0,1,2,4 (all channels)
 
              spw='<2';  spectral windows less than 2 (i.e. 0,1)
 
              spw='0:5~61'; spw 0, channels 5 to 61
 
              spw='0,10,3:3~45'; spw 0,10 all channels, spw 3, channels 3 to 45.
 
              spw='0~2:2~6'; spw 0,1,2 with channels 2 through 6 in each.
 
              spw='0:0~10;15~60'; spectral window 0 with channels 0-10,15-60
 
              spw='0:0~10,1:20~30,2:1;2;4'; spw 0, channels 0-10,
 
                      spw 1, channels 20-30, and spw 2, channels, 1,2 and 4
 
              field='3C286,3C295'; field named 3C286 adn 3C295
 
              field = '3,4C*'; field id 3, all names starting with 4C
 
      spw -- Select spectral window/channels
 
              default: ''=all spectral windows and channels
 
              spw='0~2,4'; spectral windows 0,1,2,4 (all channels)
 
              spw='<2';  spectral windows less than 2 (i.e. 0,1)
 
              spw='0:5~61'; spw 0, channels 5 to 61
 
              spw='0,10,3:3~45'; spw 0,10 all channels, spw 3, channels 3 to 45.
 
              spw='0~2:2~6'; spw 0,1,2 with channels 2 through 6 in each.
 
              spw='0:0~10;15~60'; spectral window 0 with channels 0-10,15-60
 
              spw='0:0~10,1:20~30,2:1;2;4'; spw 0, channels 0-10,
 
                      spw 1, channels 20-30, and spw 2, channels, 1,2 and 4
 
 
 
      Use one of the two methods below:  modimage or fluxdensity
 
 
 
      modimage -- Model image (I only) from which the model visibilities
 
              default: '' means do not use model, but fluxdensity
 
              Each field must be done separately.  The image clean model
 
              will be scaled from the frequency in the model to that actually used.
 
              Both the amplitude and phase are calculated.
 
              At the AOC or CV, the models are located in the
 
              /usr/lib/casapy/data/nrao/VLA/CalModels/3C286_L.im (egs)
 
                  lib64
 
 
 
      fluxdensity -- Specified flux density [I,Q,U,V] in Jy
 
              default => -1, places [1,0,0,0] flux density for all sources,
 
                  except for 3C286, 3C48 and 3C147 where the absolute flux
 
                  density it added.  It is recommended to use the modimage for
 
                  these sources if they are resolved with the observations.
 
              Only one flux density can be executed at a time.  The phases are
 
                  set to zero.
 
              example  fluxdensity=-1  will insert 1.0 for all calibrators
 
                        except 3C286, 3C147 and 3C48
 
              example  field = '1'; fluxdensity=[3.2,0,0,0] wil put in
 
                        flux density of I=3.2 for field='1'
 
 
 
              At present, this is the only method to insert a polarized flux
 
              density model (June 2000).
 
              example:  fluxdensity=[2.63,0.21,-0.33,0.02]
 
                        will put in I,Q,U,V flux densities of 2.63,0.21,-0.33,
 
                        and 0.02, respectively, in the model column.
 
 
 
      standard -- Flux density standard, used if fluxdensity<0
 
              default: 'Perley-Taylor 99'; example: standard='Baars'
 
              Options: 'Baars','Perley 90','Perley-Taylor 95',
 
                  'Perley-Taylor 99'
 
</pre>
 

Latest revision as of 15:38, 18 May 2015