pycrtools.tasks.polarization

Polarization([ws, parfile])	Calculates the angle of polarization for each antenna from the Stokes parameters (I, Q, U and V).
Task([ws, parfile])	Base class from which all tasks should be derived.
hilbert(x[, N, axis])	Compute the analytic signal, using the Hilbert transform.

Polarization

Module author: Pim Schellart <p.schellart@astro.ru.nl>

class pycrtools.tasks.polarization.Polarization(ws=None, parfile=None, **kwargs)

Calculates the angle of polarization for each antenna from the Stokes parameters (I, Q, U and V). A quiver plot, with arrows representing the polarization angles, is optionally created and stored.

Note

The task in its current form assumes that the calibrated pulse block is stored by the pipeline in the standard location.

See also

Schellart et al., Polarized radio emission from extensive air showers measured with LOFAR, Journal of Cosmology and Astroparticle Physics, Issue 10, article id. 014, pp. (2014).

Input parameters

core [default value: [0.0, 0.0, 0.0] ]

Core position (x, y, z) in meters.

core_uncertainties [default value: [5.0, 5.0, 0.0] ]

Uncertainties on core position.

data_path

Path where xyz_calibrated_pulse_block is located and where output will be stored

db

CRDB instance

dbManager

CRDB instance

direction [default value: None ]

Direction (az, el) in LOFAR convention to use for polarization, i.e. cr_average_direction

event

Event object

eventid [default value: None ]

Event ID

include_stations [default value: ['CS001', 'CS002', 'CS003', 'CS004', 'CS005', 'CS006', 'CS007', 'CS011', 'CS013', 'CS017', 'CS021'] ]

List of stations to include

plot_prefix [default value: “” ]

Prefix for plots

plot_title [default value: True ]

Plot title, turn off for publication ready figures

plot_type [default value: “png” ]

Plot type (e.g. png, jpeg, pdf)

plotlist [default value: [] ]

List of plots

pulse_integration_half_width [default value: 2 ]

Number of samples to the left and right of the pulse sample to integrate over for obtaining the Stokes parameters

save_plots [default value: False ]

Store plots

Output parameters

mean_vxb [default value: None ]

Mean of the absolute value of the polarization component of the polarization vector

mean_vxvxb [default value: None ]

Mean of the absolute value of the polarization component of the polarization vector

polarization_angle [default value: None ]

Polarization angle with the axis, positive towards in the shower plane, for each antenna

polarization_angle_uncertainty [default value: None ]

Uncertainty on polarization angle

std_vxb [default value: None ]

Standard deviation of the absolute value of the polarization component of the polarization vector

std_vxvxb [default value: None ]

Standard deviation of the absolute value of the polarization component of the polarization vector

stokes_I [default value: None ]

Stokes I for each antenna.

stokes_Q [default value: None ]

Stokes Q for each antenna.

stokes_U [default value: None ]

Stokes U for each antenna.

stokes_V [default value: None ]

Stokes V for each antenna.

run()

Run the task.