def zoom_source(self, x_pos, y_pos, kwargs_lens, source_sigma=0.003, window_size=0.1, grid_number=100,
shape="GAUSSIAN"):
"""
computes the surface brightness on an image with a zoomed window
:param x_pos: angular coordinate of center of image
:param y_pos: angular coordinate of center of image
:param kwargs_lens: lens model parameter list
:param source_sigma: source size (in angular units)
:param window_size: window size in angular units
:param grid_number: number of grid points per axis
:param shape: string, shape of source, supports 'GAUSSIAN' and 'TORUS
:return: 2d numpy array
"""
deltaPix = float(window_size) / grid_number
if shape == 'GAUSSIAN':
from lenstronomy.LightModel.Profiles.gaussian import Gaussian
quasar = Gaussian()
elif shape == 'TORUS':
import lenstronomy.LightModel.Profiles.ellipsoid as quasar
else:
raise ValueError("shape %s not valid for finite magnification computation!" % shape)
x_grid, y_grid = util.make_grid(numPix=grid_number, deltapix=deltaPix, subgrid_res=1)
center_x, center_y = self._lensModel.ray_shooting(x_pos, y_pos, kwargs_lens)
betax, betay = self._lensModel.ray_shooting(x_grid + x_pos, y_grid + y_pos, kwargs_lens)
image = quasar.function(betax, betay, 1., source_sigma, center_x, center_y)
return util.array2image(image)
def test_function(self):
"""
:return:
"""
output = torus.function(x=1,
y=1,
amp=1.,
sigma=2,
center_x=0,
center_y=0)
assert output == 0.079577471545947673
def magnification_finite(self, x_pos, y_pos, kwargs_lens, source_sigma=0.003, window_size=0.1, grid_number=100,
shape="GAUSSIAN", polar_grid=False, aspect_ratio=0.5):
"""
returns the magnification of an extended source with Gaussian light profile
:param x_pos: x-axis positons of point sources
:param y_pos: y-axis position of point sources
:param kwargs_lens: lens model kwargs
:param source_sigma: Gaussian sigma in arc sec in source
:param window_size: size of window to compute the finite flux
:param grid_number: number of grid cells per axis in the window to numerically comute the flux
:return: numerically computed brightness of the sources
"""
mag_finite = np.zeros_like(x_pos)
deltaPix = float(window_size)/grid_number
if shape == 'GAUSSIAN':
from lenstronomy.LightModel.Profiles.gaussian import Gaussian
quasar = Gaussian()
elif shape == 'TORUS':
import lenstronomy.LightModel.Profiles.ellipsoid as quasar
else:
raise ValueError("shape %s not valid for finite magnification computation!" % shape)
x_grid, y_grid = util.make_grid(numPix=grid_number, deltapix=deltaPix, subgrid_res=1)
if polar_grid is True:
a = window_size*0.5
b = window_size*0.5*aspect_ratio
ellipse_inds = (x_grid*a**-1) **2 + (y_grid*b**-1) **2 <= 1
x_grid, y_grid = x_grid[ellipse_inds], y_grid[ellipse_inds]
for i in range(len(x_pos)):
ra, dec = x_pos[i], y_pos[i]
center_x, center_y = self._lensModel.ray_shooting(ra, dec, kwargs_lens)
if polar_grid is True:
theta = np.arctan2(dec,ra)
xcoord, ycoord = util.rotate(x_grid, y_grid, theta)
else:
xcoord, ycoord = x_grid, y_grid
betax, betay = self._lensModel.ray_shooting(xcoord + ra, ycoord + dec, kwargs_lens)
I_image = quasar.function(betax, betay, 1., source_sigma, center_x, center_y)
mag_finite[i] = np.sum(I_image) * deltaPix**2
return mag_finite