# autogalaxy.profiles.mass.ExternalShear#

class ExternalShear[source]#

Bases: `MassProfile`

An ExternalShear term, to model the line-of-sight contribution of other galaxies / satellites.

The shear angle is defined in the direction of stretching of the image. Therefore, if an object located outside the lens is responsible for the shear, it will be offset 90 degrees from the value of angle.

Parameters:

gamma

Methods

 `angle_to_profile_grid_from` The angle between each angle theta on the grid and the profile, in radians. `area_within_curve_list_from` rtype: `average_convergence_of_1_radius` The radius a critical curve forms for this mass profile, e.g. `convergence_1d_from` rtype: `convergence_2d_from` `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): `convergence_func` rtype: `float` `deflections_2d_via_potential_2d_from` `deflections_yx_2d_from` Calculate the deflection angles at a given set of arc-second gridded coordinates. `density_between_circular_annuli` Calculate the mass between two circular annuli and compute the density by dividing by the annuli surface area. `eccentric_radii_grid_from` Convert a grid of (y,x) coordinates to an eccentric radius: :math: axis_ratio^0.5 (x^2 + (y^2/q))^0.5 `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. `elliptical_radii_grid_from` Convert a grid of (y,x) coordinates to their elliptical radii values: :math: (x^2 + (y^2/q))^0.5 `extract_attribute` Returns an attribute of a class and its children profiles in the galaxy as a ValueIrregular or Grid2DIrregular object. `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): `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). `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. `mass_integral` `potential_1d_from` rtype: `potential_2d_from` `potential_func` `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: `radial_grid_from` Convert a grid of (y, x) coordinates, to their radial distances from the profile centre (e.g. `rotated_grid_from_reference_frame_from` Rotate a grid of (y,x) coordinates which have been transformed to the elliptical reference frame of a profile back to the original unrotated coordinate grid reference frame. `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: `transformed_from_reference_frame_grid_from` Transform a grid of (y,x) coordinates from the reference frame of the profile to the original observer reference frame. `transformed_to_reference_frame_grid_from` Transform a grid of (y,x) coordinates to the reference frame of the profile.

Attributes

 `angle` The position angle in degrees of the major-axis of the ellipse defined by profile, defined counter clockwise from the positive x-axis (0.0 > angle > 180.0). `angle_radians` The position angle in radians of the major-axis of the ellipse defined by profile, defined counter clockwise from the positive x-axis (0.0 > angle > 2pi). `axis_ratio` The ratio of the minor-axis to major-axis (b/a) of the ellipse defined by profile (0.0 > q > 1.0). `ellipticity_rescale` `magnitude`
property angle#

The position angle in degrees of the major-axis of the ellipse defined by profile, defined counter clockwise from the positive x-axis (0.0 > angle > 180.0).

The radius a critical curve forms for this mass profile, e.g. where the mean convergence is equal to 1.0.

In case of ellipitical mass profiles, the ‘average’ critical curve is used, whereby the convergence is rescaled into a circle using the axis ratio.

This radius corresponds to the Einstein radius of the mass profile, and is a property of a number of mass profiles below.

deflections_yx_2d_from(grid)[source]#

Calculate the deflection angles at a given set of arc-second gridded coordinates.

Parameters:

grid (`Union`[`ndarray`, `Grid2D`, `Grid2DIterate`, `Grid2DIrregular`]) – The grid of (y,x) arc-second coordinates the deflection angles are computed on.