import numpy as np
from typing import Optional, Tuple
import autoarray as aa
from autogalaxy.profiles.light.abstract import LightProfile
from autogalaxy.profiles.light.decorators import (
check_operated_only,
)
[docs]class Chameleon(LightProfile):
def __init__(
self,
centre: Tuple[float, float] = (0.0, 0.0),
ell_comps: Tuple[float, float] = (0.0, 0.0),
intensity: float = 0.1,
core_radius_0: float = 0.01,
core_radius_1: float = 0.05,
):
"""
The elliptical Chameleon light profile.
This light profile closely approximes the Elliptical Sersic light profile, by representing it as two cored
elliptical isothermal profiles. This is convenient for lensing calculations, because the deflection angles of
an isothermal profile can be evaluated analyticially efficiently.
Parameters
----------
centre
The (y,x) arc-second coordinates of the profile centre.
ell_comps
The first and second ellipticity components of the elliptical coordinate system.
intensity
Overall intensity normalisation of the light profile (units are dimensionless and derived from the data
the light profile's image is compared too, which is expected to be electrons per second).
core_radius_0
The core size of the first elliptical cored Isothermal profile.
core_radius_1
The core size of the second elliptical cored Isothermal profile.
"""
super().__init__(centre=centre, ell_comps=ell_comps, intensity=intensity)
self.core_radius_0 = core_radius_0
self.core_radius_1 = core_radius_1
@property
def axis_ratio(self) -> float:
"""
The elliptical isothermal mass profile deflection angles break down for perfectly spherical systems where
`axis_ratio=1.0`, thus we remove these solutions.
"""
axis_ratio = super().axis_ratio
return axis_ratio if axis_ratio < 0.99999 else 0.99999
[docs] def image_2d_via_radii_from(self, grid_radii: np.ndarray) -> np.ndarray:
"""
Returns the 2D image of the Sersic light profile from a grid of coordinates which are the radial distances of
each coordinate from the its `centre`.
Parameters
----------
grid_radii
The radial distances from the centre of the profile, for each coordinate on the grid.
"""
axis_ratio_factor = (1.0 + self.axis_ratio) ** 2.0
return np.multiply(
self._intensity / (1 + self.axis_ratio),
np.add(
np.divide(
1.0,
np.sqrt(
np.add(
np.square(grid_radii),
(4.0 * self.core_radius_0**2.0) / axis_ratio_factor,
)
),
),
-np.divide(
1.0,
np.sqrt(
np.add(
np.square(grid_radii),
(4.0 * self.core_radius_1**2.0) / axis_ratio_factor,
)
),
),
),
)
[docs] @aa.grid_dec.grid_2d_to_structure
@check_operated_only
@aa.grid_dec.transform
@aa.grid_dec.relocate_to_radial_minimum
def image_2d_from(
self, grid: aa.type.Grid2DLike, operated_only: Optional[bool] = None
) -> np.ndarray:
"""
Returns the Chameleon light profile's 2D image from a 2D grid of Cartesian (y,x) coordinates.
If the coordinates have not been transformed to the profile's geometry (e.g. translated to the
profile `centre`), this is performed automatically.
Parameters
----------
grid
The 2D (y, x) coordinates in the original reference frame of the grid.
Returns
-------
image
The image of the Chameleon evaluated at every (y,x) coordinate on the transformed grid.
"""
return self.image_2d_via_radii_from(self.elliptical_radii_grid_from(grid))
[docs]class ChameleonSph(Chameleon):
def __init__(
self,
centre: Tuple[float, float] = (0.0, 0.0),
intensity: float = 0.1,
core_radius_0: float = 0.01,
core_radius_1: float = 0.05,
):
"""
The spherical Chameleon light profile.
This light profile closely approximes the Elliptical Sersic light profile, by representing it as two cored
elliptical isothermal profiles. This is convenient for lensing calculations, because the deflection angles of
an isothermal profile can be evaluated analyticially efficiently.
Parameters
----------
centre
The (y,x) arc-second coordinates of the profile centre.
ell_comps
The first and second ellipticity components of the elliptical coordinate system.
intensity
Overall intensity normalisation of the light profile (units are dimensionless and derived from the data
the light profile's image is compared too, which is expected to be electrons per second).
core_radius_0
The core size of the first elliptical cored Isothermal profile.
core_radius_1
The core size of the second elliptical cored Isothermal profile.
"""
super().__init__(
centre=centre,
ell_comps=(0.0, 0.0),
intensity=intensity,
core_radius_0=core_radius_0,
core_radius_1=core_radius_1,
)