Point plus extended lens simulation

This notebook shows how to use SLSim to simulate point plus extended source lens. For

this, it uses a simple point plus extended source catalog. Catalog has skypy galaxaly

catalog as host galaxies and fake quasars as point source.

Simulate source and deflector population

import matplotlib.pyplot as plt
from astropy.cosmology import FlatLambdaCDM
from astropy.units import Quantity
from slsim.lens_pop import LensPop
from slsim.image_simulation import lens_image
import numpy as np

# define a cosmology
cosmo = FlatLambdaCDM(H0=70, Om0=0.3)


# define a sky area
sky_area = Quantity(value=1, unit="deg2")


# define limits in the intrinsic deflector and source population (in addition to the
# skypy config
# file)
kwargs_deflector_cut = {"band": "g", "band_max": 23, "z_min": 0.01, "z_max": 2.5}
kwargs_source_cut = {"band": "g", "band_max": 26, "z_min": 0.1, "z_max": 5.0}

## create a point plus extended source lens population.
pes_lens_pop = LensPop(
    deflector_type="all-galaxies",
    source_type="quasar_plus_galaxies",
    kwargs_deflector_cut=kwargs_deflector_cut,
    kwargs_source_cut=kwargs_source_cut,
    variability_model="sinusoidal",
    kwargs_variability={"amp", "freq"},
    kwargs_mass2light=None,
    skypy_config=None,
    sky_area=sky_area,
    cosmo=cosmo,
)

Select a lens at random

# Define a lens cut
kwargs_lens_cut = {"min_image_separation": 0.8, "max_image_separation": 10}
# Select a lens at random
pes_lens_class = pes_lens_pop.select_lens_at_random(**kwargs_lens_cut)

Define a psf kernel and tranform matrix

# load your psf kernel and transform matrix
psf_kernel = np.load("../..//tests/TestData/psf_kernels_for_deflector.npy")
transform_matrix = np.array([[0.2, 0], [0, 0.2]])

Simulate lens image

# Simulate a lens image
image_lens = lens_image(
    lens_class=pes_lens_class,
    band="i",
    mag_zero_point=27,
    num_pix=64,
    psf_kernel=psf_kernel,
    transform_pix2angle=transform_matrix,
    exposure_time=30,
)

/Users/sanchez/.virtualenvs/slsim/lib/python3.12/site-packages/lenstronomy/Data/psf.py:80: UserWarning: Input PSF model has at least one negative element, which is unphysical except for a PSF of an interferometric array.
  warnings.warn(

plt.imshow(image_lens)

<matplotlib.image.AxesImage at 0x14fcc4320>