import matplotlib.pyplot as plt
import numpy as np
from astropy.modeling.models import Gaussian2D
from astropy.visualization import simple_norm
from photutils.datasets import make_noise_image

# Create an artificial single source
gmodel = Gaussian2D(42.1, 47.8, 52.4, 4.7, 4.7, 0)
yy, xx = np.mgrid[0:100, 0:100]
data = gmodel(xx, yy)
bkg_sig = 2.1
noise = make_noise_image(data.shape, mean=0., stddev=bkg_sig, seed=0)
data += noise
error = np.zeros_like(data) + bkg_sig

fig, ax = plt.subplots(figsize=(5, 5))
norm = simple_norm(data, 'sqrt')
ax.imshow(data, norm=norm, origin='lower')