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NRAO Home > CASA > CASA Task Reference Manual |
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0.1.32 ft
Requires:
Synopsis
Insert a source model a visibility set:
Description
A source model (souce.model image) or components list is converted into
model visibilities that is inserted into the MODEL_DATA column or
alternatively is stored in the header of the MS to be served on the fly when
requested. This is needed to use more complicated sources than setjy provides;
e.g resolved source or off centered sources in gaincal. (Setjy will automatically
make this ft step.)
The sources currently available are 3C48, 3C138, 3C147, 3C286 at 1.4, 5.0, 8.4,
15, 22, 43 GHz. Their location is site dependent. In Charlottesville and at the
SOC, the models are in /usr/lib/casapy/data/nrao/VLA/CalModels.
Arguments
Inputs |
| ||
vis |
| Name of input visibility file (MS)
| |
| allowed: | string |
|
| Default: |
| |
field |
| Field selection
| |
| allowed: | string |
|
| Default: |
| |
spw |
| Spw selection
| |
| allowed: | string |
|
| Default: |
|
|
model |
| Name of input model image(s)
| |
| allowed: | any |
|
| Default: | variant
|
|
nterms |
| Number of terms used to model the sky frequency
dependence
| |
| allowed: | int |
|
| Default: | 1 |
|
reffreq |
| Reference frequency (e.g. ’1.5e+9’ or ’1.5GHz’)
| |
| allowed: | string |
|
| Default: |
|
|
complist |
| Name of component list
| |
| allowed: | string |
|
| Default: |
|
|
incremental |
| Add to the existing model visibility?
| |
| allowed: | bool |
|
| Default: | False |
|
usescratch |
| If True predicted visibility is stored in MODEL_DATA
column
| |
| allowed: | bool |
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| Default: | False |
|
void
Example
A source model (souce.model image) or components list is converted into a
model visibility that is inserted into the MODEL_DATA column. This is
needed to use resolved source in gaincal and in fluxscale.
Setjy will automatically make this ft step on the
sources currently available are 3C48, 3C138, 3C147, 3C286
at 1.4, 5.0, 8.4, 15, 22, 43 GHz. Their location is site
dependent. In Charlottesville and at the AOC, the models are
in /usr/lib(lib64)/casapy/data/nrao/VLA/CalModels.
Keyword arguments:
vis -- Name of input visibility file
default: none; example: vis=’ngc5921.ms’
field -- Field name list
default: ’’ ==> all
NOTE: BUT, only one source can be specified in a multi-source vis.
field = ’1328+307’ specifies source ’1328+307’
field = ’4’ specified field with index 4
spw -- Spw selection
default: spw = ’’ (all spw)
model -- Name of input model image
default: ’’ ==> None;
example: model=’/usr/lib/casapy/data/nrao/VLA/CalModels/3C286_X.im’
Note: The model visibilities are scaled from the model frequency
to the observed frequency of the data.
nterms -- Number of terms used to model the sky frequency dependence
default: 1 ==> one model image is required
example : nterms=3 represents a 2nd order Taylor-polynomial in frequency
and should be used in conjuction with coefficient model images as
model=[’xxx.model.tt0’,’xxx.model.tt1’, ’xxx.model.tt2’]
reffreq -- Reference-frequency about which this Taylor-expansion is defined.
default: ’’ ==> reads the reference frequency from the model image
example : reffreq = ’1.5GHz’
complist -- Name of component list
default: None; ; example: complist=’test.cl’
component lists are difficult to make.
incremental -- Add model visibility to the existing model visibilties stored in the MS
default: False; example: incremental=True
usescratch -- if True model visibilities will be stored in the scratch column
MODEL_DATA; when false the model visibilities will be generated
on the fly (this mode may save some disk space equivalent to
the volume of the observed data).
default: False; example usescratch=True
More information about CASA may be found at the
CASA web page
Copyright © 2016 Associated Universities Inc., Washington, D.C.
This code is available under the terms of the GNU General Public Lincense
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