Description

This task makes a flux model as a component list from one of the flux calibrator standards used by the setjy task. It also returns a Python dictionary of the predicted model and optionally plots the predicted visibility amplitudes versus uv-distance when the array configuration information is specified. It uses the same common prediction code as setjy but without the need for the actual visibility data. This task is useful for cross checking what setjy would set for model visilibilities or for finding a predicted flux density for a calibrator at a particular epoch, especially when the flux calibrator is a Solar System object.

The following are the main keys of the returned dictionary (or False on error):

  • 'antennalist' - array configuration file
  • 'savedfig' - output file name for a plot
  • 'spectrum' - frequency setup information
  • 'clist' - output component list name
  • 'riseset' - times of rise and set of the object 
  • 'standard' - flux standard used
  • 'shape' - model shape and position of the object
  • 'epoch' - epoch used 
  • 'objname' - object name
  • 'freqs (GHz)' - frequencies
  • 'amps' - list of predicted visibility amplitudes
  • 'baselines' - list of baselines
  • 'blunit' - unit
  • 'azel' - AZ-El direction

 

Parameter descriptions

objname

The object name as recognized by setjy. If the object specified is not visible from the specified telescope, an error will be thrown to this effect.

standard

Sets the flux density model standard from setjy, namely Perley-Taylor 99, Baars, Perley 90, Perley-Taylor 95, Butler-JPL-Horizons 2010, Butler-JPL-Horizons 2012.

epoch

Sets the time that predictcomp uses, which is only relevant for Solar Object standards, using a standard CASA date/time format (e.g., '2018-12-31/5:34:12').

minfreq

Sets the minimum predicted frequency of the model. Units must be given. Examples: minfreq='230GHz'

maxfreq

Sets the maximum predicted frequency of the model. Units must be given. Examples: maxfreq='265GHz'

nfreqs

Sets the frequency interval for the predicted visibilities. Examples: minfreq='230GHz' maxfreqs='265GHz' nfreqs=5, the predicted visibilities will be determined for frequencies of equal interval determined by the equation $(maxfreqs - minfreqs) / nfreqs$ (in this case, for frequencies 230, 239, 248, 256, and 265 GHz).

prefix

The component list will be saved to ' + _spw0_.cl'. If a component list of the same name already exists, predictcomp will remove the previous version. Default: ' ' which will create the component list name sans the prefix. Examples: prefix='Bands3to7_', which could produce 'Bands3to7_Uranus_spw0_100GHz55877d.cl' (depending on the other parameters).

antennalist

When antennalist is given a valid array configuration file, the task predicts and plots (if set) the visibility amplitudes for the array configuration. The search path is: .:casa['dirs']['data'] + '/alma/simmos/'. Default: '', None just makes a component list. Examples: antennalist='alma.cycle0.extended.cfg'

antennalist expandable parameters

showplot

Whether or not to show a plot of the visibility amplitudes vs. uv distance on the screen.

savefig

Filename for saving a plot of the amplitude vs. uv distances.

symb

One of matplotlib's codes for plot symbols: .:,o^v<>s+xDd234hH|_. Default: '.'

include0amp

Force the amplitude axis to start at 0. Default: False

include0bl

Force the baseline axis to start at 0. Default: False

blunit

Unit of the baseline axis ('' or 'klambda'). Default: ' ' = use a unit in the data

showbl0flux

Print the zero baseline flux. Default: False