StokesSpectralCube¶

class spectral_cube.StokesSpectralCube(stokes_data, mask=None, meta=None, fill_value=None)[source]¶

Bases: object

A class to store a spectral cube with multiple Stokes parameters.

The individual Stokes cubes can share a common mask in addition to having component-specific masks.

Attributes Summary

`components`
`mask`	The underlying mask
`read`	Read and parse a dataset and return as a StokesSpectralCube
`shape`
`stokes_data`	The underlying data
`stokes_type`	Defines the type of stokes that has been setup. `stokes_type` can be sky, linear, circular, generic, or other.
`wcs`
`write`	Write this StokesSpectralCube object out in the specified format.

Methods Summary

`transform_basis`([stokes_basis])	The goal of this function is to transform the stokes basis of the cube to the one specified if possible.
`with_mask`(mask[, inherit_mask])	Return a new StokesSpectralCube instance that contains a composite mask of the current StokesSpectralCube and the new `mask`.
`with_spectral_unit`(unit, **kwargs)

Attributes Documentation

components¶

mask¶: The underlying mask

read¶

Read and parse a dataset and return as a StokesSpectralCube

This allows easily reading a dataset in several supported data formats using syntax such as:

>>> from spectral_cube import StokesSpectralCube
>>> cube1 = StokesSpectralCube.read('cube.fits', format='fits')
>>> cube2 = StokesSpectralCube.read('cube.image', format='casa')

If the file contains Stokes axes, they will be read in. If you are only interested in the unpolarized emission (I), you can use read() instead.

Get help on the available readers for StokesSpectralCube using the``help()`` method:

>>> StokesSpectralCube.read.help()  # Get help reading StokesSpectralCube and list supported formats
>>> StokesSpectralCube.read.help('fits')  # Get detailed help on StokesSpectralCube FITS reader
>>> StokesSpectralCube.read.list_formats()  # Print list of available formats

Parameters:

*argstuple, optional: Positional arguments passed through to data reader. If supplied the first argument is typically the input filename.
formatstr: File format specifier.
**kwargsdict, optional: Keyword arguments passed through to data reader.

Returns:

cubeStokesSpectralCube: StokesSpectralCube corresponding to dataset

shape¶

stokes_data¶: The underlying data

stokes_type¶

Defines the type of stokes that has been setup. stokes_type can be sky, linear, circular, generic, or other.

Sky refers to stokes in sky basis, I,Q,U,V
Linear refers to the stokes in linear feed basis, XX, XY, YX, YY
Circular refers to stokes in circular feed basis, RR, RL, LR, LL
Generic refers to the general four orthogonal components, PP, PQ, QP, QQ

wcs¶

write¶

Write this StokesSpectralCube object out in the specified format.

This allows easily writing a dataset in many supported data formats using syntax such as:

>>> data.write('data.fits', format='fits')

Get help on the available writers for StokesSpectralCube using the``help()`` method:

>>> StokesSpectralCube.write.help()  # Get help writing StokesSpectralCube and list supported formats
>>> StokesSpectralCube.write.help('fits')  # Get detailed help on StokesSpectralCube FITS writer
>>> StokesSpectralCube.write.list_formats()  # Print list of available formats

Parameters:

*argstuple, optional: Positional arguments passed through to data writer. If supplied the first argument is the output filename.
formatstr: File format specifier.
**kwargsdict, optional: Keyword arguments passed through to data writer.

Methods Documentation

transform_basis(stokes_basis='')[source]¶

The goal of this function is to transform the stokes basis of the cube to the one specified if possible. In principle one needs at least two related stokes of a given basis for the transformation to be possible. At this moment we are limiting it to the cases where all four stokes parameters in a given basis be available within the cube. The transformations are as follows Linear to Sky I = (XX + YY) / 2 Q = (XX - YY) / 2 U = (XY + YX) / 2 V = 1j(XY - YX) / 2

Circular to Sky I = (RR + LL) / 2 Q = (RL + LR) / 2 U = 1j*(RL - LR) / 2 V = (RR - LL) / 2

with_mask(mask, inherit_mask=True)[source]¶

Return a new StokesSpectralCube instance that contains a composite mask of the current StokesSpectralCube and the new mask.

Parameters:

maskMaskBase instance, or boolean numpy array: The mask to apply. If a boolean array is supplied, it will be converted into a mask, assuming that True values indicate included elements.
inherit_maskbool (optional, default=True): If True, combines the provided mask with the mask currently attached to the cube

Returns:

new_cubeStokesSpectralCube: A cube with the new mask applied.

Notes

This operation returns a view into the data, and not a copy.

with_spectral_unit(unit, **kwargs)[source]¶

Navigation

StokesSpectralCube¶