autolens.Galaxy#

class Galaxy[source]#

Bases: ModelObject, OperateImageList, OperateDeflections

Class representing a galaxy, which is composed of attributes used for fitting galaxies (e.g. light profiles, mass profiles, pixelizations, etc.).

All has_ methods retun True if galaxy has that attribute, False if not.

Parameters:

redshift (float) – The redshift of the galaxy.
pixelization – The pixelization of the galaxy used to reconstruct an observed image using an inversion.

Methods

`area_within_curve_list_from`	rtype: `List`[`float`]
`blurred_image_2d_from`	Evaluate the light object's 2D image from a input 2D grid of coordinates and convolve it with a PSF.
`blurred_image_2d_list_from`	Evaluate the light object's list of 2D images from a input 2D grid of coordinates and convolve each image with a PSF.
`cls_list_from`	Returns a list of objects in the galaxy which are an instance of the input cls.
`convergence_1d_from`	Returns the summed 1D convergence of the galaxy's mass profiles using a grid of Cartesian (y,x) coordinates.
`convergence_2d_from`	Returns the summed 2D convergence of the galaxy's mass profiles from a 2D grid of Cartesian (y,x) coordinates.
`convergence_2d_via_hessian_from`	Returns the convergence of the lensing object, which is computed from the 2D deflection angle map via the Hessian using the expression (see equation 56 https://inspirehep.net/literature/419263):
`convergence_2d_via_jacobian_from`	Returns the convergence of the lensing object, which is computed from the 2D deflection angle map via the Jacobian using the expression (see equation 58 https://inspirehep.net/literature/419263):
`deflections_yx_2d_from`	Returns the summed 2D deflection angles of the galaxy's mass profiles from a 2D grid of Cartesian (y,x) coordinates.
`dict`	A dictionary representation of this object
`einstein_mass_angular_from`	Returns the Einstein radius corresponding to the area within the tangential critical curve.
`einstein_mass_angular_list_from`	Returns a list of the angular Einstein massses corresponding to the area within each tangential critical curve.
`einstein_radius_from`	Returns the Einstein radius corresponding to the area within the tangential critical curve.
`einstein_radius_list_from`	Returns a list of the Einstein radii corresponding to the area within each tangential critical curve.
`extract_attribute`	Returns an attribute of a class and its children profiles in the galaxy as a ValueIrregular or Grid2DIrregular object.
`from_dict`	Recursively parse a dictionary returning the model, collection or instance that is represents.
`grid_radial_from`
`has`	Does this instance have an attribute which is of type cls?
`hessian_from`	Returns the Hessian of the lensing object, where the Hessian is the second partial derivatives of the potential (see equation 55 https://inspirehep.net/literature/419263):
`image_1d_from`	Returns the summed 1D image of the galaxy's light profiles using a grid of Cartesian (y,x) coordinates.
`image_2d_from`	Returns the 2D image of all galaxy light profiles summed from a 2D grid of Cartesian (y,x) coordinates.
`image_2d_list_from`	Returns a list of the 2D images of the galaxy's light profiles from a 2D grid of Cartesian (y,x) coordinates.
`jacobian_from`	Returns the Jacobian of the lensing object, which is computed by taking the gradient of the 2D deflection angle map in four direction (positive y, negative y, positive x, negative x).
`luminosity_within_circle_from`	Returns the total luminosity of the galaxy's light profiles within a circle of specified radius.
`magnification_2d_from`	Returns the 2D magnification map of lensing object, which is computed as the inverse of the determinant of the jacobian.
`magnification_2d_via_hessian_from`	Returns the 2D magnification map of lensing object, which is computed from the 2D deflection angle map via the Hessian using the expressions (see equation 60 https://inspirehep.net/literature/419263):
`mass_angular_within_circle_from`	Integrate the mass profiles's convergence profile to compute the total mass within a circle of specified radius.
`next_id`
`padded_image_2d_from`	Evaluate the light object's 2D image from a input 2D grid of padded coordinates, where this padding is sufficient to encapsulate all surrounding pixels that will blur light into the original image given the 2D shape of the PSF's kernel.
`potential_1d_from`	Returns the summed 1D potential of the galaxy's mass profiles using a grid of Cartesian (y,x) coordinates.
`potential_2d_from`	Returns the summed 2D potential of the galaxy's mass profiles from a 2D grid of Cartesian (y,x) coordinates.
`radial_caustic_list_from`	Returns all radial caustics of the lensing system, which are computed as follows:
`radial_critical_curve_area_list_from`	Returns the surface area within each radial critical curve as a list, the calculation of which is described in the function radial_critical_curve_list_from().
`radial_critical_curve_list_from`	Returns all radial critical curves of the lensing system, which are computed as follows:
`radial_eigen_value_from`	Returns the radial eigen values of lensing jacobian, which are given by the expression:
`replacing_for_path`	Create a new model replacing the value for a given path with a new value
`set_snr_of_snr_light_profiles`	Iterate over every galaxy finding all LightProfileSNR light profiles and set their intensity values to values which give their input signal_to_noise_ratio value, which is performed as follows:
`shear_yx_2d_via_hessian_from`	Returns the 2D (y,x) shear vectors of the lensing object, which are computed from the 2D deflection angle map via the Hessian using the expressions (see equation 57 https://inspirehep.net/literature/419263):
`shear_yx_2d_via_jacobian_from`	Returns the 2D (y,x) shear vectors of the lensing object, which are computed from the 2D deflection angle map via the Jacobian using the expression (see equation 58 https://inspirehep.net/literature/419263):
`tangential_caustic_list_from`	Returns all tangential caustics of the lensing system, which are computed as follows:
`tangential_critical_curve_area_list_from`	Returns the surface area within each tangential critical curve as a list, the calculation of which is described in the function tangential_critical_curve_list_from().
`tangential_critical_curve_list_from`	Returns all tangential critical curves of the lensing system, which are computed as follows:
`tangential_eigen_value_from`	Returns the tangential eigen values of lensing jacobian, which are given by the expression:
`traced_grid_2d_from`	Trace an input grid using the galaxy's its deflection angles.
`unmasked_blurred_image_2d_from`	Evaluate the light object's 2D image from a input 2D grid of coordinates and convolve it with a PSF, using a grid which is not masked.
`unmasked_blurred_image_2d_list_from`	Evaluate the light object's list of 2D images from a input 2D grid of coordinates and convolve it with a PSF, using a grid which is not masked.
`visibilities_from`	Evaluate the light object's 2D image from a input 2D grid of coordinates and transform this to an array of visibilities using a autoarray.operators.transformer.Transformer object and therefore a Fourier Transform.
`visibilities_list_from`	Evaluate the light object's list of 2D image from a input 2D grid of coordinates and transform each image to arrays of visibilities using a autoarray.operators.transformer.Transformer object and therefore a Fourier Transform.

Attributes

`component_number`
`half_light_radius`
`identifier`
`label`
`profile_dict`	rtype: `Dict`

dict()[source]#

A dictionary representation of this object

Return type:: Dict

cls_list_from(cls, cls_filtered=None)[source]#

Returns a list of objects in the galaxy which are an instance of the input cls.

The optional cls_filtered input removes classes of an input instance type.

For example:

If the input is cls=ag.LightProfile, a list containing all light profiles in the galaxy is returned.
If cls=ag.LightProfile and cls_filtered=ag.LightProfileLinear, a list of all light profiles excluding those which are linear light profiles will be returned.

Parameters:

cls (Type) – The type of class that a list of instances of this class in the galaxy are returned for.
cls_filtered (Optional[Type]) – A class type which is filtered and removed from the class list.

Return type:

The list of objects in the galaxy that inherit from input cls.

image_2d_list_from(grid, operated_only=None)[source]#

Returns a list of the 2D images of the galaxy’s light profiles from a 2D grid of Cartesian (y,x) coordinates.

If the galaxy has no light profiles, a numpy array of zeros is returned.

The images output by this function do not include instrument operations, such as PSF convolution (for imaging data) or a Fourier transform (for interferometer data).

Inherited methods in the autogalaxy.operate.image package can apply these operations to the images. These functions may have the operated_only input passed to them, which is why this function includes the operated_only input.

If the operated_only input is included, the function omits light profiles which are parents of the LightProfileOperated object, which signifies that the light profile represents emission that has already had the instrument operations (e.g. PSF convolution, a Fourier transform) applied to it and therefore that operation is not performed again.

See the autogalaxy.profiles.light package for details of how images are computed from a light profile.

Parameters:

grid (Union[ndarray, Grid2D, Grid2DIterate, Grid2DIrregular]) – The 2D (y, x) coordinates where values of the image are evaluated.
operated_only (Optional[bool]) – By default, the returnd list contains all light profile images (irrespective of whether they have been operated on or not). If this input is included as a bool, only images which are or are not already operated are included in the list, with the images of other light profiles created as a numpy array of zeros.

Return type:

List[Array2D]

image_2d_from(grid, operated_only=None)[source]#

Returns the 2D image of all galaxy light profiles summed from a 2D grid of Cartesian (y,x) coordinates.

This function first computes the image of each galaxy, via the function image_2d_list_from. The images are then summed to give the overall image of the galaxies.

Refer to the function image_2d_list_from for a full description of the calculation and how the operated_only input is used.

Parameters:

grid (Union[ndarray, Grid2D, Grid2DIterate, Grid2DIrregular]) – The 2D (y, x) coordinates where values of the image are evaluated.
operated_only (Optional[bool]) – The returned list from this function contains all light profile images, and they are never operated on (e.g. via the imaging PSF). However, inherited methods in the autogalaxy.operate.image package can apply these operations to the images, which may have the operated_only input passed to them. This input therefore is used to pass the operated_only input to these methods.

Return type:

Union[ndarray, Array2D]

image_1d_from(grid)[source]#

Returns the summed 1D image of the galaxy’s light profiles using a grid of Cartesian (y,x) coordinates.

If the galaxy has no light profiles, a grid of zeros is returned.

See profiles.light module for details of how this is performed.

The decorator grid_1d_output_structure converts the output arrays from ndarrays to an Array1D data structure using the input grid’s attributes.

Parameters:: grid (Union[ndarray, Grid2D, Grid2DIterate, Grid2DIrregular]) – The 1D (x,) coordinates where values of the image are evaluated.
Return type:: ndarray

deflections_yx_2d_from(grid)[source]#

Returns the summed 2D deflection angles of the galaxy’s mass profiles from a 2D grid of Cartesian (y,x) coordinates.

If the galaxy has no mass profiles, a numpy array of zeros is returned.

See the autogalaxy.profiles.mass package for details of how deflection angles are computed from a mass profile.

The decorator grid_2d_to_vector_yx converts the output arrays from ndarrays to a VectorYX2D data structure using the input grid’s attributes.

Parameters:: grid (Union[ndarray, Grid2D, Grid2DIterate, Grid2DIrregular]) – The 2D (y, x) coordinates where values of the deflection angles are evaluated.
Return type:: ndarray

convergence_2d_from(grid)[source]#

Returns the summed 2D convergence of the galaxy’s mass profiles from a 2D grid of Cartesian (y,x) coordinates.

If the galaxy has no mass profiles, a numpy array of zeros is returned.

See the autogalaxy.profiles.mass package for details of how convergences are computed from a mass profile.

The decorator grid_2d_to_structure converts the output arrays from ndarrays to an Array2D data structure using the input grid’s attributes.

Parameters:: grid (Union[ndarray, Grid2D, Grid2DIterate, Grid2DIrregular]) – The 2D (y, x) coordinates where values of the convergence are evaluated.
Return type:: ndarray

traced_grid_2d_from(grid)[source]#

Trace an input grid using the galaxy’s its deflection angles.

Return type:: Union[ndarray, Grid2D, Grid2DIterate, Grid2DIrregular]

convergence_1d_from(grid)[source]#

Returns the summed 1D convergence of the galaxy’s mass profiles using a grid of Cartesian (y,x) coordinates.

If the galaxy has no mass profiles, a grid of zeros is returned.

See profiles.mass module for details of how this is performed.

The decorator grid_1d_output_structure converts the output arrays from ndarrays to an Array1D data structure using the input grid’s attributes.

Parameters:: grid (Union[ndarray, Grid1D, Grid2D, Grid2DIterate, Grid2DIrregular]) – The 1D (x,) coordinates where values of the convergence are evaluated.
Return type:: ndarray

potential_2d_from(grid)[source]#

Returns the summed 2D potential of the galaxy’s mass profiles from a 2D grid of Cartesian (y,x) coordinates.

If the galaxy has no mass profiles, a numpy array of zeros is returned.

See the autogalaxy.profiles.mass package for details of how potentials are computed from a mass profile.

The decorator grid_2d_to_structure converts the output arrays from ndarrays to an Array2D data structure using the input grid’s attributes.

Parameters:: grid (Union[ndarray, Grid2D, Grid2DIterate, Grid2DIrregular]) – The 2D (y, x) coordinates where values of the potential are evaluated.
Return type:: ndarray

potential_1d_from(grid)[source]#

Returns the summed 1D potential of the galaxy’s mass profiles using a grid of Cartesian (y,x) coordinates.

If the galaxy has no mass profiles, a grid of zeros is returned.

See profiles.mass module for details of how this is performed.

The decorator grid_1d_output_structure converts the output arrays from ndarrays to an Array1D data structure using the input grid’s attributes.

Parameters:: grid (Union[ndarray, Grid2D, Grid2DIterate, Grid2DIrregular]) – The 1D (x,) coordinates where values of the potential are evaluated.
Return type:: ndarray

extract_attribute(cls, attr_name)[source]#

Returns an attribute of a class and its children profiles in the galaxy as a ValueIrregular or Grid2DIrregular object.

For example, if a galaxy has two light profiles and we want the LightProfile axis-ratios, the following:

galaxy.extract_attribute(cls=LightProfile, name=”axis_ratio”

would return:

ArrayIrregular(values=[axis_ratio_0, axis_ratio_1])

If a galaxy has three mass profiles and we want the MassProfile centres, the following:

galaxy.extract_attribute(cls=MassProfile, name=”centres”

would return:

GridIrregular2D(grid=[(centre_y_0, centre_x_0), (centre_y_1, centre_x_1), (centre_y_2, centre_x_2)])

This is used for visualization, for example plotting the centres of all light profiles colored by their profile.

luminosity_within_circle_from(radius)[source]#

Returns the total luminosity of the galaxy’s light profiles within a circle of specified radius.

See light_profile.luminosity_within_circle for details of how this is performed.

Parameters:

radius (float) – The radius of the circle to compute the dimensionless mass within.
unit_luminosity – The unit_label the luminosity is returned in {esp, counts}.
exposure_time – The exposure time of the observation, which converts luminosity from electrons per second unit_label to counts.

mass_angular_within_circle_from(radius)[source]#

Integrate the mass profiles’s convergence profile to compute the total mass within a circle of specified radius. This is centred on the mass profile.

The following unit_label for mass can be specified and output:

Dimensionless angular unit_label (default) - ‘angular’.
Solar masses - ‘angular’ (multiplies the angular mass by the critical surface mass density).

Parameters:

radius (dim.Length) – The radius of the circle to compute the dimensionless mass within.
unit_mass – The unit_label the mass is returned in {angular, angular}.
None (critical_surface_density or) – The critical surface mass density of the strong lens configuration, which converts mass from angulalr unit_label to phsical unit_label (e.g. solar masses).

set_snr_of_snr_light_profiles(grid, exposure_time, background_sky_level=0.0, psf=None)[source]#

Iterate over every galaxy finding all LightProfileSNR light profiles and set their intensity values to values which give their input signal_to_noise_ratio value, which is performed as follows:

Evaluate the image of each light profile on the input grid.
Blur this image with a PSF, if included.
Take the value of the brightest pixel.
Use an input exposure_time and background_sky (e.g. from the SimulatorImaging object) to determine what value of intensity gives the desired signal to noise ratio for the image.

Parameters:

grid (Union[ndarray, Grid2D, Grid2DIterate, Grid2DIrregular]) – The (y, x) coordinates in the original reference frame of the grid.
exposure_time (float) – The exposure time of the simulated imaging.
background_sky_level (float) – The level of the background sky of the simulated imaging.
psf (Optional[Kernel2D]) – The psf of the simulated imaging which can change the S/N of the light profile due to spreading out the emission.