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<casaxml xmlns="http://casa.nrao.edu/schema/psetTypes.html"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://casa.nrao.edu/schema/casa.xsd
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file:///opt/casa/code/xmlcasa/xml/casa.xsd">
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<task type="function" name="ft" category="imaging, calibration">
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<shortdescription>Insert a source model a visibility set:</shortdescription>
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<description>
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A source model (souce.model image) or components list is converted into
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model visibilities that is inserted into the MODEL_DATA column or alternatively
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is stored in the header of the MS to be served on the fly when requested. This is
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needed to use more complicated sources than setjy provides; e.g resolved source
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or off centered sources in gaincal. (Setjy will
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automatically make this ft step.)
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The sources currently available are 3C48, 3C138, 3C147, 3C286
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at 1.4, 5.0, 8.4, 15, 22, 43 GHz. Their location is site
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dependent. In Charlottesville and at the SOC, the models are
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in /usr/lib/casapy/data/nrao/VLA/CalModels.
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</description>
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<input>
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<param type="string" name="vis" mustexist="true">
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<description>Name of input visibility file (MS)</description>
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<value></value>
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</param>
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<param type="string" name="field">
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<description>Field selection</description>
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<value></value>
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</param>
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<param type="string" name="spw">
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<description>Spw selection</description>
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<value></value>
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</param>
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<param type="any" name="model">
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<description>Name of input model image(s)</description>
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<any type="variant"/>
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<value type="string"></value>
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</param>
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<param type="int" name="nterms">
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<description>Number of terms used to model the sky frequency dependence</description>
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<value>1</value>
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</param>
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<param type="string" name="reffreq" subparam="true">
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<description>Reference frequency (e.g. \'1.5e+9\' or \'1.5GHz\')</description>
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<value></value>
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</param>
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<param type="string" name="complist">
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<description>Name of component list</description>
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<value></value>
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</param>
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<param type="bool" name="incremental">
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<description>Add to the existing model visibility?</description>
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<value>False</value>
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</param>
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<param type="bool" name="usescratch">
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<description>If True predicted visibility is stored in MODEL_DATA column</description>
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<value>False</value>
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</param>
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<constraints>
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<when param="nterms">
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<notequals type="int" value="1">
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<default param="reffreq"><value type="string"></value></default>
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</notequals>
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</when>
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</constraints>
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</input>
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<returns type="void"/>
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<example>
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A source model (souce.model image) or components list is converted into a
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model visibility that is inserted into the MODEL_DATA column. This is
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needed to use resolved source in gaincal and in fluxscale.
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Setjy will automatically make this ft step on the
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sources currently available are 3C48, 3C138, 3C147, 3C286
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at 1.4, 5.0, 8.4, 15, 22, 43 GHz. Their location is site
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dependent. In Charlottesville and at the AOC, the models are
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in /usr/lib(lib64)/casapy/data/nrao/VLA/CalModels.
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Keyword arguments:
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vis -- Name of input visibility file
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default: none; example: vis='ngc5921.ms'
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field -- Field name list
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default: '' ==> all
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NOTE: BUT, only one source can be specified in a multi-source vis.
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field = '1328+307' specifies source '1328+307'
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field = '4' specified field with index 4
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spw -- Spw selection
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default: spw = '' (all spw)
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model -- Name of input model image
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default: '' ==> None;
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example: model='/usr/lib/casapy/data/nrao/VLA/CalModels/3C286_X.im'
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Note: The model visibilities are scaled from the model frequency
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to the observed frequency of the data.
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nterms -- Number of terms used to model the sky frequency dependence
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default: 1 ==> one model image is required
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example : nterms=3 represents a 2nd order Taylor-polynomial in frequency
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and should be used in conjuction with coefficient model images as
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model=['xxx.model.tt0','xxx.model.tt1', 'xxx.model.tt2']
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reffreq -- Reference-frequency about which this Taylor-expansion is defined.
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default: '' ==> reads the reference frequency from the model image
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example : reffreq = '1.5GHz'
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complist -- Name of component list
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default: None; ; example: complist='test.cl'
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component lists are difficult to make.
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incremental -- Add model visibility to the existing model visibilties stored in the MS
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default: False; example: incremental=True
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usescratch -- if True model visibilities will be stored in the scratch column
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MODEL_DATA; when false the model visibilities will be generated
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on the fly (this mode may save some disk space equivalent to
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the volume of the observed data).
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default: False; example usescratch=True
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</example>
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</task>
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</casaxml>