Source code for lenstronomy.LensModel.Profiles.nfw_ellipse

__author__ = 'sibirrer'

import numpy as np
from lenstronomy.LensModel.Profiles.nfw import NFW
import lenstronomy.Util.param_util as param_util
from lenstronomy.LensModel.Profiles.base_profile import LensProfileBase

__all__ = ['NFW_ELLIPSE']


[docs]class NFW_ELLIPSE(LensProfileBase): """ this class contains functions concerning the NFW profile with an ellipticity defined in the potential parameterization of alpha_Rs and Rs is the same as for the spherical NFW profile from Glose & Kneib: https://cds.cern.ch/record/529584/files/0112138.pdf relation are: R_200 = c * Rs """ param_names = ['Rs', 'alpha_Rs', 'e1', 'e2', 'center_x', 'center_y'] lower_limit_default = {'Rs': 0, 'alpha_Rs': 0, 'e1': -0.5, 'e2': -0.5, 'center_x': -100, 'center_y': -100} upper_limit_default = {'Rs': 100, 'alpha_Rs': 10, 'e1': 0.5, 'e2': 0.5, 'center_x': 100, 'center_y': 100} def __init__(self, interpol=False, num_interp_X=1000, max_interp_X=10): self.nfw = NFW(interpol=interpol, num_interp_X=num_interp_X, max_interp_X=max_interp_X) self._diff = 0.0000000001 super(NFW_ELLIPSE, self).__init__()
[docs] def function(self, x, y, Rs, alpha_Rs, e1, e2, center_x=0, center_y=0): """ returns elliptically distorted NFW lensing potential :param x: angular position (normally in units of arc seconds) :param y: angular position (normally in units of arc seconds) :param Rs: turn over point in the slope of the NFW profile in angular unit :param alpha_Rs: deflection (angular units) at projected Rs :param e1: eccentricity component in x-direction :param e2: eccentricity component in y-direction :param center_x: center of halo (in angular units) :param center_y: center of halo (in angular units) :return: lensing potential """ phi_G, q = param_util.ellipticity2phi_q(e1, e2) x_shift = x - center_x y_shift = y - center_y cos_phi = np.cos(phi_G) sin_phi = np.sin(phi_G) e = min(abs(1. - q), 0.9999) xt1 = (cos_phi*x_shift+sin_phi*y_shift)*np.sqrt(1 - e) xt2 = (-sin_phi*x_shift+cos_phi*y_shift)*np.sqrt(1 + e) R_ = np.sqrt(xt1**2 + xt2**2) rho0_input = self.nfw._alpha2rho0(alpha_Rs=alpha_Rs, Rs=Rs) if Rs < 0.0000001: Rs = 0.0000001 f_ = self.nfw.nfwPot(R_, Rs, rho0_input) return f_
[docs] def derivatives(self, x, y, Rs, alpha_Rs, e1, e2, center_x=0, center_y=0): """ returns df/dx and df/dy of the function, calculated as an elliptically distorted deflection angle of the spherical NFW profile :param x: angular position (normally in units of arc seconds) :param y: angular position (normally in units of arc seconds) :param Rs: turn over point in the slope of the NFW profile in angular unit :param alpha_Rs: deflection (angular units) at projected Rs :param e1: eccentricity component in x-direction :param e2: eccentricity component in y-direction :param center_x: center of halo (in angular units) :param center_y: center of halo (in angular units) :return: deflection in x-direction, deflection in y-direction """ phi_G, q = param_util.ellipticity2phi_q(e1, e2) x_shift = x - center_x y_shift = y - center_y cos_phi = np.cos(phi_G) sin_phi = np.sin(phi_G) e = min(abs(1. - q), 0.9999) xt1 = (cos_phi*x_shift+sin_phi*y_shift)*np.sqrt(1 - e) xt2 = (-sin_phi*x_shift+cos_phi*y_shift)*np.sqrt(1 + e) R_ = np.sqrt(xt1**2 + xt2**2) rho0_input = self.nfw._alpha2rho0(alpha_Rs=alpha_Rs, Rs=Rs) if Rs < 0.0000001: Rs = 0.0000001 f_x_prim, f_y_prim = self.nfw.nfwAlpha(R_, Rs, rho0_input, xt1, xt2) f_x_prim *= np.sqrt(1 - e) f_y_prim *= np.sqrt(1 + e) f_x = cos_phi*f_x_prim-sin_phi*f_y_prim f_y = sin_phi*f_x_prim+cos_phi*f_y_prim return f_x, f_y
[docs] def hessian(self, x, y, Rs, alpha_Rs, e1, e2, center_x=0, center_y=0): """ returns Hessian matrix of function d^2f/dx^2, d^f/dy^2, d^2/dxdy the calculation is performed as a numerical differential from the deflection field. Analytical relations are possible :param x: angular position (normally in units of arc seconds) :param y: angular position (normally in units of arc seconds) :param Rs: turn over point in the slope of the NFW profile in angular unit :param alpha_Rs: deflection (angular units) at projected Rs :param e1: eccentricity component in x-direction :param e2: eccentricity component in y-direction :param center_x: center of halo (in angular units) :param center_y: center of halo (in angular units) :return: d^2f/dx^2, d^2/dxdy, d^2/dydx, d^f/dy^2 """ alpha_ra, alpha_dec = self.derivatives(x, y, Rs, alpha_Rs, e1, e2, center_x, center_y) diff = self._diff alpha_ra_dx, alpha_dec_dx = self.derivatives(x + diff, y, Rs, alpha_Rs, e1, e2, center_x, center_y) alpha_ra_dy, alpha_dec_dy = self.derivatives(x, y + diff, Rs, alpha_Rs, e1, e2, center_x, center_y) f_xx = (alpha_ra_dx - alpha_ra)/diff f_xy = (alpha_ra_dy - alpha_ra)/diff f_yx = (alpha_dec_dx - alpha_dec)/diff f_yy = (alpha_dec_dy - alpha_dec)/diff return f_xx, f_xy, f_yx, f_yy
[docs] def mass_3d_lens(self, R, Rs, alpha_Rs, e1=1, e2=0): """ :param R: radius (in angular units) :param Rs: :param alpha_Rs: :param e1: :param e2: :return: """ return self.nfw.mass_3d_lens(R, Rs, alpha_Rs)
[docs] def density_lens(self, r, Rs, alpha_Rs, e1=1, e2=0): """ computes the density at 3d radius r given lens model parameterization. The integral in the LOS projection of this quantity results in the convergence quantity. :param r: 3d radios :param Rs: turn-over radius of NFW profile :param alpha_Rs: deflection at Rs :return: density rho(r) """ return self.nfw.density_lens(r, Rs, alpha_Rs)