polcal

Carry out polarization calibration of the data (leakage and polarization angle).

enable

bool, optional, default = True

Execute the polcal worker.

label_in

str, optional, default = ‘ ‘

Label of the .MS file(s) to work on.

label_cal

str, optional, default = 1pcal

Label for output files (calibration tables, images).

otfcal

Apply on-the-fly (OTF) calibration.

enable

bool, optional, default = False

Enable the ‘otfcal’ segment.

callib

str, optional, default = ‘ ‘

Name of the callib file to be used, if user has their own. A corresponding .json file must exist.

label_cal

str, optional, default = ‘ ‘

Label of the calibration tables to be used.

interpolation

Overrides interpolations settings for OTF calibration

delay_cal

{“default”, “nearest”, “linear”, “nearestPD”, “linearPD”}, optional, default = nearest

Interpolation type (in time) for K-Jones (delay) solutions. ‘nearest’ is recommended for CASA, as ‘linear’ can produce unexpected results.

gain_cal

{“default”, “nearest”, “linear”, “nearestPD”, “linearPD”}, optional, default = linear

Interpolation type (in time) for G-Jones (gain) solutions.

bp_cal

{“default”, “nearest”, “linear”, “nearestPD”, “linearPD”}, optional, default = linear

Interpolation type (in time) for B-Jones (bandpass) solutions.

extendflags

bool, optional, default = False

use casa_flagdata with mode=extend to flag data which have been already flagged more than 70%. This can improve calibration.

feed_angle_rotation

float, optional, default = ‘ ‘

Set the rotation angle for feeds. For MeerKAT data it is suggested to rotate the feeds by -90 degrees to agree with the convention assumed in the CASA software which is used to do the polarization calibration. Leave it empty if you don’t want to rotate the feeds.

rewind_flags

Rewind flags to specified version.

enable

bool, optional, default = True

Enable the rewind_flags segement.

mode

{“reset_worker”, “rewind_to_version”}, optional, default = reset_worker

If mode = ‘reset_worker’ rewind to the flag version before this worker if it exists, or continue if it does not exist; if mode = ‘rewind_to_version’ rewind to the flag version given by ‘version’ below.

version

str, optional, default = auto

Flag version to rewind to. If ‘auto’ it will rewind to the version prefix_workername_before, where ‘prefix’ is set in the ‘general’ worker, and ‘workername’ is the name of this worker including the suffix ‘__X’ if it is a repeated instance of this worker in the configuration file. Note that all flag versions that had been saved after this version will be deleted.

overwrite_flagvers

bool, optional, default = False

Allow Caracal to overwrite existing flag versions. Not recommended. Only enable this if you know what you are doing.

uvrange

str, optional, default = >50

Select what UV range should be used throughout this worker following the CASA notation (e.g., “>100”). The default units are metres but other units can be used (e.g., “>0.5klambda”).

reuse_existing_tables

bool, optional, default = True

Use existing pcal tables

pol_calib

{“xcal”, “none”}, optional, default = xcal

calibrator for the polarized angle.

leakage_calib

{“fcal”, “bpcal”, “xcal”, “gcal”}, optional, default = fcal

leakage calibrator. It could be either a known unpolarized calibrator or a polarized calibrator observed at several parallactic angles.

set_model_leakage

Fill in the MODEL column of the .MS file(s) for the leakage calibrator in preparation for polcalibration. Not necessary if you are using the same .MS file(s) of crosscal, it is if you splitted cross calibrated data to execute this worker and if leakage_calib != pol_calib.

enable

bool, optional, default = False

Execute the set_model_leakage segment.

meerkat_skymodel

bool, optional, default = False

Use the MeerkAT local sky model (lsm) of the calibrator instead of a point source model. At the moment a MeerKAT lsm is only available for the calibrator PKS 1934-638. For the calibrator 0408-6545 a model is available but is not well tested yet and we do not recommend using it.

no_verify

bool, optional, default = False

Enables setting standard manually [???].

tile_size

int, optional, default = 128

Size of tile (time bins) to process. Can be used to reduce memory footprint.

threads

int, optional, default = 8

Number of threads used by MeqTrees if meerkat_skymodel above is enabled.

set_model_pol

bool, optional, default = True

Fill in the MODEL column of the .MS file(s) for the polarized calibrator in preparation for polcalibration. This can be done only for 3C138 and 3C286 using the CASA setjy for point-source models. If False it will derive the model by fitting the PA coverage. This can be done only if more than 3 scans have been acquired. Not recomended for small PAs coverage.

freqsel

str, optional, default = ‘ ‘

Subband selection to be used whenever solving for the DC component of either X or D. This could be picked to avoid RFI. Not used if not set or if set_model_pol is False.

gain_solint

str, optional, default = inf

Time solution interval to be used for gaincal. Set to ‘int’ if set_model_pol is False.

time_solint

str, optional, default = inf

Time solution interval to be used whenever solving for the DC component of either X or D

plotgains

bool, optional, default = True

Plot solutions with ragavi-gains. The .html plots are located in <output>/diagnostic_plots/polcal/.

apply_pcal

bool, optional, default = True

Apply the polcal solutions (together with the otfcal solution if that segment is set to True) to the .MS file(s).

applyto

list of str, optional, default = xcal, bpcal, gcal, target

Fields to apply calibration to.

summary

Prints out the butcher’s bill, i.e. data flagging summary at the end of pol calibration process.

enable

bool, optional, default = True

Execute printing flagging summary.

report

bool, optional, default = False

(Re)generate a full HTML report at the end of this worker.

cabs

list of map, optional, default = ‘ ‘

Specifies non-default image versions and/or tags for Stimela cabs. Running with scissors: use with extreme caution.