Simulating an astronomical image¶

Running a realistic image simulation to compare with actual data (as it is done while constraining the galaxy population) requires a lot of work to correctly model the background and PSF for all real images. We give an example how to generate a simple image with constant PSF and background level. Note that the location of the image is not defined via a healpy map anymore but by defining the center of the image, the pixel scale and the number of pixels. We choose values for the image systematics that are represantative for HSC deep fields.

model = GalSBI("Fischbacher+24")
model(mode="image")

The image is save under {catalog_name}_{model_index}_{band}_image.fits but can also be loaded using load_images directly

from astropy.visualization import ImageNormalize, LogStretch
from astropy.visualization.mpl_normalize import ImageNormalize
from astropy.visualization import ZScaleInterval, PercentileInterval
import matplotlib.pyplot as plt

images = model.load_images()
image = images["image i"]

interval = PercentileInterval(95)
vmin, vmax = interval.get_limits(image)
norm = ImageNormalize(vmin=vmin, vmax=vmax)

plt.imshow(image, cmap='gray', norm=norm)