def test_update_source_redshift(self):
z_source = 1.5
lens_model_list = ['SIS']
kwargs_lens = [{'theta_E': 1}]
redshift_list = [0.5]
lensModelMutli = MultiPlane(z_source=z_source, lens_model_list=lens_model_list,
lens_redshift_list=redshift_list)
alpha_x, alpha_y = lensModelMutli.alpha(1, 0, kwargs_lens=kwargs_lens)
lensModelMutli.update_source_redshift(z_source=z_source)
alpha_x_new, alpha_y_new = lensModelMutli.alpha(1, 0, kwargs_lens=kwargs_lens)
npt.assert_almost_equal(alpha_x/alpha_x_new, 1., decimal=8)
lensModelMutli.update_source_redshift(z_source=1.)
alpha_x_new, alpha_y_new = lensModelMutli.alpha(1, 0, kwargs_lens=kwargs_lens)
assert alpha_x / alpha_x_new > 1
lensModelMutli.update_source_redshift(z_source=2.)
alpha_x_new, alpha_y_new = lensModelMutli.alpha(1, 0, kwargs_lens=kwargs_lens)
assert alpha_x / alpha_x_new < 1
def test_sis_alpha(self):
z_source = 1.5
lens_model_list = ['SIS']
redshift_list = [0.5]
lensModelMutli = MultiPlane(z_source=z_source, lens_model_list=lens_model_list, lens_redshift_list=redshift_list)
lensModel = LensModel(lens_model_list=lens_model_list)
kwargs_lens = [{'theta_E': 1, 'center_x': 0, 'center_y': 0}]
alpha_x_simple, alpha_y_simple = lensModel.alpha(1, 0, kwargs_lens)
alpha_x_multi, alpha_y_multi = lensModelMutli.alpha(1, 0, kwargs_lens)
npt.assert_almost_equal(alpha_x_simple, alpha_x_multi, decimal=8)
npt.assert_almost_equal(alpha_y_simple, alpha_y_multi, decimal=8)
sum_partial = np.sum(lensModelMutli._multi_plane_base._T_ij_list) + lensModelMutli._T_ij_stop
T_z_true = lensModelMutli._T_z_source
npt.assert_almost_equal(sum_partial, T_z_true, decimal=5)
def test_foreground_shear(self):
"""
scenario: a shear field in the foreground of the main deflector is placed
we compute the expected shear on the lens plain and effectively model the same system in a single plane
configuration
We check for consistency of the two approaches and whether the specific redshift of the foreground shear field has
an impact on the arrival time surface
:return:
"""
z_source = 1.5
z_lens = 0.5
z_shear = 0.2
x, y = np.array([1., 0.]), np.array([0., 2.])
from astropy.cosmology import default_cosmology
from lenstronomy.Cosmo.background import Background
cosmo = default_cosmology.get()
cosmo_bkg = Background(cosmo)
e1, e2 = 0.01, 0.01 # shear terms caused by z_shear on z_source
lens_model_list = ['SIS', 'SHEAR']
redshift_list = [z_lens, z_shear]
lensModelMutli = MultiPlane(z_source=z_source,
lens_model_list=lens_model_list,
lens_redshift_list=redshift_list)
kwargs_lens_multi = [{
'theta_E': 1,
'center_x': 0,
'center_y': 0
}, {
'e1': e1,
'e2': e2
}]
alpha_x_multi, alpha_y_multi = lensModelMutli.alpha(
x, y, kwargs_lens_multi)
t_multi = lensModelMutli.arrival_time(x, y, kwargs_lens_multi)
dt_multi = t_multi[0] - t_multi[1]
physical_shear = cosmo_bkg.D_xy(0, z_source) / cosmo_bkg.D_xy(
z_shear, z_source)
foreground_factor = cosmo_bkg.D_xy(z_shear, z_lens) / cosmo_bkg.D_xy(
0, z_lens) * physical_shear
print(foreground_factor)
lens_model_simple_list = ['SIS', 'FOREGROUND_SHEAR', 'SHEAR']
kwargs_lens_single = [{
'theta_E': 1,
'center_x': 0,
'center_y': 0
}, {
'e1': e1 * foreground_factor,
'e2': e2 * foreground_factor
}, {
'e1': e1,
'e2': e2
}]
lensModel = LensModel(lens_model_list=lens_model_simple_list)
alpha_x_simple, alpha_y_simple = lensModel.alpha(
x, y, kwargs_lens_single)
npt.assert_almost_equal(alpha_x_simple, alpha_x_multi, decimal=8)
npt.assert_almost_equal(alpha_y_simple, alpha_y_multi, decimal=8)
ra_source, dec_source = lensModel.ray_shooting(x, y,
kwargs_lens_single)
ra_source_multi, dec_source_multi = lensModelMutli.ray_shooting(
x, y, kwargs_lens_multi)
npt.assert_almost_equal(ra_source, ra_source_multi, decimal=8)
npt.assert_almost_equal(dec_source, dec_source_multi, decimal=8)
fermat_pot = lensModel.fermat_potential(x, y, ra_source, dec_source,
kwargs_lens_single)
from lenstronomy.Cosmo.lens_cosmo import LensCosmo
lensCosmo = LensCosmo(z_lens, z_source, cosmo=cosmo)
Dt = lensCosmo.D_dt
print(lensCosmo.D_dt)
#t_simple = const.delay_arcsec2days(fermat_pot, Dt)
t_simple = lensCosmo.time_delay_units(fermat_pot)
dt_simple = t_simple[0] - t_simple[1]
print(t_simple, t_multi)
npt.assert_almost_equal(dt_simple / dt_multi, 1, decimal=2)
