setjy – Fills the model column with the visibilities of a calibrator – modeling, calibration task

Description

This task places the model visibility amp and phase associated with a specified clean components image into the model column of the data set. The flux density (I,Q,U,V) for a point source calibrator can be entered explicitly.

Models are available for 3C48, 3C138, and 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 models are presently available.

The location of the models is system dependent: At the AOC, the models are in the directory::/usr/lib/casapy/data/nrao/VLA/CalModels/ 3C286_L.im (egs)

setjy need only be run on the calibrator sources with a known flux density and/or model.

For Solar System Objects, model determination was updated and it is available via the ‘Butler-JPL-Horizons 2012’ standard.

Currently they are modeled as uniform temperature disks based on their ephemeris at the time of observation (note that this may oversimplify objects, in particular asteroids). Specify the name of the object in the ‘field’ parameter.

Parameters

Title
Parameter	Default	Description
vis	`''`
field	`''`
spw	`''`
selectdata	`False`
timerange	`''`
scan	`''`
intent	`''`
observation	`''`
scalebychan	`True`
standard	`'Perley-Butler 2013'`
model	`''`
modimage	`''`
listmodels	`False`
fluxdensity	`int(-1)`
spix	`float(0.0)`
reffreq	`'1GHz'`
polindex	`numpy.array( [ ] )`
polangle	`numpy.array( [ ] )`
rotmeas	`float(0.0)`
fluxdict	`{ }`
useephemdir	`False`
interpolation	`'nearest'`
usescratch	`False`
ismms	`False`
fluxd	`[ ]`

Parameter Explanations

vis

''

Name of input visibility file

field

''

Field name(s)

spw

''

Spectral window identifier (list)

selectdata

False

Other data selection parameters

timerange

''

Time range to operate on (for usescratch=T)

scan

''

Scan number range (for usescaratch=T)

intent

''

Observation intent

observation

''

Observation ID range (for usescratch=T)

scalebychan

True

scale the flux density on a per channel basis or else on a per spw basis

standard

'Perley-Butler 2013'

Flux density standard

model

''

File location for field model

modimage

''

File location for field model

listmodels

False

List the available modimages for VLA calibrators or Tb models for Solar System objects

fluxdensity

int(-1)

Specified flux density [I,Q,U,V]; (-1 will lookup values)

spix

float(0.0)

Spectral index (including higher terms) of I fluxdensity

reffreq

'1GHz'

Reference frequency for spix

polindex

numpy.array( [ ] )

Coefficients of an expansion of frequency-dependent linear polarization fraction expression

polangle

numpy.array( [ ] )

Coefficients of an expansion of frequency-dependent polarization angle expression

rotmeas

float(0.0)

Rotation measure (in rad/m^2)

fluxdict

{ }

output dictionary from fluxscale

useephemdir

False

use directions in the ephemeris table

interpolation

'nearest'

method to be used to interpolate in time

usescratch

False

Will create if necessary and use the MODEL_DATA

ismms

False

to be used internally for MMS

fluxd

[ ]

Dictionary containing flux densities and their errors.