code: def half_light_radius_source(self, kwargs_source, center_x=0, center_y=0, deltaPix=None, numPix=None):
          
          if numPix is None:
              numPix = 1000
          if deltaPix is None:
              deltaPix = 0.005
          x_grid, y_grid = util.make_grid(numPix=numPix, deltapix=deltaPix)
          x_grid += center_x
          y_grid += center_y
          source_light = self.SourceModel.surface_brightness(x_grid, y_grid, kwargs_source)
          R_h = analysis_util.half_light_radius(source_light, x_grid, y_grid, center_x=center_x, center_y=center_y)
          return R_h
docs: computes numerically the half-light-radius of the deflector light and the total photon flux
  
          :param kwargs_source:
          :return: