fluxscale – Bootstrap the flux density scale from standard calibrators – calibration task

Description

Bootstrap the flux density scale from standard calibrators.

Parameters

Title

Parameter	Default	Description
vis	''	Name of input visibility file
caltable	''	Name of input calibration table
fluxtable	''	Name of output, flux-scaled calibration table (required)
reference	numpy.array( [  ] )	Reference field name(s) (transfer flux scale FROM)
transfer	numpy.array( [  ] )	Transfer field name(s) (transfer flux scale TO), '' -> all
listfile	''	Name of listfile that contains the fit information. Default is ‘’ (no file).
append	False	Append solutions?
refspwmap	numpy.array( [  ] )	Scale across spectral window boundaries
gainthreshold	float(-1.0)	Threshold (fractional deviation from the median) on gain amplitudes to be used in the flux scale calculation
antenna	''	Select data based on antenna/baseline
timerange	''	Select data based on time range
scan	''	Scan number range
incremental	False	Incremental caltable
fitorder	int(1)	Order of spectral fitting
display	False	Display some statistics of flux scaling
fluxd	[ ]

Parameter Explanations

vis

''

Name of input visibility file

Default: none

Example: vis=’ngc5921.ms’

caltable

''

Name of input calibration table

Default: none

Example: caltable=’ngc5921.gcal’. This cal table was obtained from task gaincal.=

fluxtable

''

Name of output, flux-scaled calibration table (required)

Default: none

Example: fluxtable=’ngc5921.gcal2’

The gains in this table have been adjusted by the derived flux density each calibrator. The MODEL_DATA column has NOT been updated for the flux density of the calibrator. Use setjy to do this if it is a point source.

reference

numpy.array( [  ] )

Reference field name(s) (transfer flux scale FROM)

Default: none

Example: reference=’1328+307’

The names of the fields with a known flux densities or visibilities that have been placed in the MODEL column by setjy or ft for a model not in the CASA system. The syntax is similar to field. Hence field index or names can be used.

transfer

numpy.array( [  ] )

Transfer field name(s) (transfer flux scale TO)

Default: ‘’ (all sources in caltable that are not specified as reference sources. Do not include unknown target sources)

The names of the fields with unknown flux densities. These should be point-like calibrator sources The syntax is similar to field. Hence source index or names can be used.

Examples: transfer=’1445+099, 3C84’; transfer = ‘0,4’

NOTE: All fields in reference and transfer must have solutions in the caltable.

listfile

''

Name of listfile that contains the fit information.

Default: ‘’ (no fit listfile will be created)

The list file contains the flux density, flux density error, S/N, and number of solutions (all antennas and feeds) for each spectral window. NOTE: The nominal spectral window frequencies will be included in the future.

append

False

Append fluxscaled solutions to the fluxtable?

Default: False (the fluxtable must not exist) Options: False|True

refspwmap

numpy.array( [  ] )

Vector of spectral windows enabling scaling across spectral windows

Default: [-1] (none)

Example with 4 spectral windows: If the reference fields were observed only in spw=1 and 3, and the transfer fields were observed in all 4 spws (0,1,2,3), specify refspwmap=[1,1,3,3]. This will ensure that transfer fields observed in spws 0,1,2,3 will be referenced to reference field solutions only in spw 1 or 3.

gainthreshold

float(-1.0)

Threshold in the input gain solutions to be used in fractional deviation from median values.

Default: -1 (no threshold)

Example: gainthreshold=0.15 (only used the gain solutions within 15% (inclusive) of the median gain value (per field and per spw).

antenna

''

Select data based on antenna/baseline

Subparameter of antenna Default: ‘’ (all)

If antenna string is a non-negative integer, it is assumed an antenna index, otherwise, it is assumed as an antenna name

Examples: antenna=’5&6’; baseline between antenna index 5 and index 6. antenna=’VA05&VA06’; baseline between VLA antenna 5 and 6. antenna=’5&6;7&8’; baselines with indices 5-6 and 7-8 antenna=’5’; all baselines with antenna index 5 antenna=’05’; all baselines with antenna number 05 (VLA old name) antenna=’5,6,10’; all baselines with antennas 5,6,10 index numbers

timerange

''

Select data based on time range

Subparameter of antenna Default = ‘’ (all)

Examples: timerange = ‘YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss’ (Note: if YYYY/MM/DD is missing date defaults to first day in data set.) timerange=’09:14:0~09:54:0’ picks 40 min on first day timerange= ‘25:00:00~27:30:00’ picks 1 hr to 3 hr 30min on NEXT day timerange=’09:44:00’ pick data within one integration of time timerange=’>10:24:00’ data after this time

scan

''

Scan number range

Subparameter of antenna Default: ‘’ = all

incremental

False

Create an incremental caltable containing only gain correction factors ( flux density= 1/(gain correction factor)**2)?

Default: False Options: False|True

Example: incremental=True (output a caltable containing flux scale factors.)

NOTE: If you use the incremental option, note that BOTH this incremental fluxscale table AND an amplitude vs. time table should be supplied in applycal.

fitorder

int(1)

Polynomial order of the spectral fitting for valid flux densities

Default: 1

It falls back to a lower fitorder if there are not enough solutions to fit with the requested fitorder.

display

False

Display statistics and/or spectral fitting results.

Default: False Options: False|True

Currently only a histogram of the correction factors to derive the final flux density for each spectral window will be plotted.

fluxd

[ ]

Dictionary containing the transfer fluxes and their errors.