import matplotlib.pyplot as plt 
from scipy.stats import gaussian_kde
from mpl_toolkits.axes_grid1 import make_axes_locatable
xy = np.vstack([x,y])
z = gaussian_kde(xy)(xy)
idx = z.argsort()
x, y, z = x[idx], y[idx], z[idx]
fig, ax = plt.subplots(figsize=(7,5),dpi=100)
scatter = ax.scatter(x,y,marker='o',c=z,edgecolors='',s=15,label='LST'
                     ,cmap='Spectral_r')
divider = make_axes_locatable(ax)
cax = divider.append_axes("right", size="5%", pad=0.1)
cbar = fig.colorbar(scatter, cax=cax, label='frequency')